Re: [PATCH v4 1/6] treewide: use prandom_u32_max() when possible, mechanically

Darrick J. Wong
2022-10-07T21:14:43Z

On Fri, Oct 07, 2022 at 12:01:02PM -0600, Jason A. Donenfeld wrote:
> Rather than incurring a division or requesting too many random bytes for
> the given range, use the prandom_u32_max() function, which only takes
> the minimum required bytes from the RNG and avoids divisions. This was
> done mechanically with these coccinelle scripts:
>
> @no_modulo@
> expression E;
> @@
> - (prandom_u32() % (E))
> + prandom_u32_max(E)
> @no_modulo@
> expression E;
> @@
> - (get_random_u32() % (E))
> + prandom_u32_max(E)
> @no_modulo@
> expression E;
> @@
> - (get_random_int() % (E))
> + prandom_u32_max(E)
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: KP Singh <kpsingh@kernel.org>
> Reviewed-by: Jan Kara <jack@suse.cz> # for ext4 and sbitmap
> Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # for mmc
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

For the XFS part,
Acked-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
> arch/arm/kernel/process.c | 2 +-
> arch/s390/kernel/vdso.c | 2 +-
> arch/um/kernel/process.c | 2 +-
> arch/x86/entry/vdso/vma.c | 2 +-
> arch/x86/kernel/module.c | 2 +-
> arch/x86/kernel/process.c | 2 +-
> arch/x86/mm/pat/cpa-test.c | 4 +-
> crypto/testmgr.c | 86 +++++++++----------
> .../gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +-
> drivers/infiniband/core/cma.c | 2 +-
> drivers/infiniband/hw/cxgb4/id_table.c | 4 +-
> drivers/infiniband/hw/hns/hns_roce_ah.c | 5 +-
> drivers/infiniband/ulp/rtrs/rtrs-clt.c | 3 +-
> .../test-drivers/vivid/vivid-touch-cap.c | 2 +-
> drivers/mmc/core/core.c | 4 +-
> drivers/mmc/host/dw_mmc.c | 2 +-
> drivers/mtd/nand/raw/nandsim.c | 4 +-
> drivers/mtd/tests/mtd_nandecctest.c | 10 +--
> drivers/mtd/ubi/debug.c | 2 +-
> .../chelsio/inline_crypto/chtls/chtls_io.c | 4 +-
> drivers/net/hamradio/baycom_epp.c | 2 +-
> drivers/net/hamradio/hdlcdrv.c | 2 +-
> drivers/net/hamradio/yam.c | 2 +-
> drivers/net/phy/at803x.c | 2 +-
> .../broadcom/brcm80211/brcmfmac/p2p.c | 2 +-
> .../net/wireless/intel/iwlwifi/mvm/mac-ctxt.c | 2 +-
> drivers/scsi/fcoe/fcoe_ctlr.c | 4 +-
> drivers/scsi/qedi/qedi_main.c | 2 +-
> fs/ceph/inode.c | 2 +-
> fs/ceph/mdsmap.c | 2 +-
> fs/ext4/super.c | 7 +-
> fs/f2fs/gc.c | 2 +-
> fs/f2fs/segment.c | 8 +-
> fs/ubifs/debug.c | 8 +-
> fs/ubifs/lpt_commit.c | 12 +--
> fs/xfs/xfs_error.c | 2 +-
> kernel/bpf/core.c | 4 +-
> kernel/locking/test-ww_mutex.c | 4 +-
> kernel/time/clocksource.c | 2 +-
> lib/cmdline_kunit.c | 4 +-
> lib/fault-inject.c | 2 +-
> lib/find_bit_benchmark.c | 4 +-
> lib/reed_solomon/test_rslib.c | 4 +-
> lib/sbitmap.c | 2 +-
> lib/test-string_helpers.c | 2 +-
> lib/test_hexdump.c | 10 +--
> lib/test_kasan.c | 6 +-
> lib/test_list_sort.c | 2 +-
> mm/migrate.c | 2 +-
> mm/slub.c | 2 +-
> net/ceph/mon_client.c | 2 +-
> net/ceph/osd_client.c | 2 +-
> net/core/neighbour.c | 2 +-
> net/core/pktgen.c | 39 ++++-----
> net/core/stream.c | 2 +-
> net/ipv4/igmp.c | 6 +-
> net/ipv4/inet_connection_sock.c | 2 +-
> net/ipv6/addrconf.c | 8 +-
> net/ipv6/mcast.c | 10 +--
> net/netfilter/ipvs/ip_vs_twos.c | 4 +-
> net/packet/af_packet.c | 2 +-
> net/sched/act_gact.c | 2 +-
> net/sched/act_sample.c | 2 +-
> net/sched/sch_netem.c | 4 +-
> net/sctp/socket.c | 2 +-
> net/tipc/socket.c | 2 +-
> net/xfrm/xfrm_state.c | 2 +-
> 67 files changed, 173 insertions(+), 177 deletions(-)
>
> diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
> index 3d9cace63884..35129ae36067 100644
> --- a/arch/arm/kernel/process.c
> +++ b/arch/arm/kernel/process.c
> @@ -375,7 +375,7 @@ static unsigned long sigpage_addr(const struct mm_struct *mm,
>
> slots = ((last - first) >> PAGE_SHIFT) + 1;
>
> - offset = get_random_int() % slots;
> + offset = prandom_u32_max(slots);
>
> addr = first + (offset << PAGE_SHIFT);
>
> diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
> index 5075cde77b29..a6b5db59cf40 100644
> --- a/arch/s390/kernel/vdso.c
> +++ b/arch/s390/kernel/vdso.c
> @@ -226,7 +226,7 @@ static unsigned long vdso_addr(unsigned long start, unsigned long len)
> end -= len;
>
> if (end > start) {
> - offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
> + offset = prandom_u32_max(((end - start) >> PAGE_SHIFT) + 1);
> addr = start + (offset << PAGE_SHIFT);
> } else {
> addr = start;
> diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
> index 80b90b1276a1..010bc422a09d 100644
> --- a/arch/um/kernel/process.c
> +++ b/arch/um/kernel/process.c
> @@ -356,7 +356,7 @@ int singlestepping(void * t)
> unsigned long arch_align_stack(unsigned long sp)
> {
> if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
> - sp -= get_random_int() % 8192;
> + sp -= prandom_u32_max(8192);
> return sp & ~0xf;
> }
> #endif
> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
> index 1000d457c332..b64c58c6940f 100644
> --- a/arch/x86/entry/vdso/vma.c
> +++ b/arch/x86/entry/vdso/vma.c
> @@ -327,7 +327,7 @@ static unsigned long vdso_addr(unsigned long start, unsigned len)
> end -= len;
>
> if (end > start) {
> - offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1);
> + offset = prandom_u32_max(((end - start) >> PAGE_SHIFT) + 1);
> addr = start + (offset << PAGE_SHIFT);
> } else {
> addr = start;
> diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
> index b1abf663417c..c032edcd3d95 100644
> --- a/arch/x86/kernel/module.c
> +++ b/arch/x86/kernel/module.c
> @@ -53,7 +53,7 @@ static unsigned long int get_module_load_offset(void)
> */
> if (module_load_offset == 0)
> module_load_offset =
> - (get_random_int() % 1024 + 1) * PAGE_SIZE;
> + (prandom_u32_max(1024) + 1) * PAGE_SIZE;
> mutex_unlock(&module_kaslr_mutex);
> }
> return module_load_offset;
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 58a6ea472db9..c21b7347a26d 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -965,7 +965,7 @@ early_param("idle", idle_setup);
> unsigned long arch_align_stack(unsigned long sp)
> {
> if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
> - sp -= get_random_int() % 8192;
> + sp -= prandom_u32_max(8192);
> return sp & ~0xf;
> }
>
> diff --git a/arch/x86/mm/pat/cpa-test.c b/arch/x86/mm/pat/cpa-test.c
> index 0612a73638a8..423b21e80929 100644
> --- a/arch/x86/mm/pat/cpa-test.c
> +++ b/arch/x86/mm/pat/cpa-test.c
> @@ -136,10 +136,10 @@ static int pageattr_test(void)
> failed += print_split(&sa);
>
> for (i = 0; i < NTEST; i++) {
> - unsigned long pfn = prandom_u32() % max_pfn_mapped;
> + unsigned long pfn = prandom_u32_max(max_pfn_mapped);
>
> addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
> - len[i] = prandom_u32() % NPAGES;
> + len[i] = prandom_u32_max(NPAGES);
> len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
>
> if (len[i] == 0)
> diff --git a/crypto/testmgr.c b/crypto/testmgr.c
> index 5349ffee6bbd..be45217acde4 100644
> --- a/crypto/testmgr.c
> +++ b/crypto/testmgr.c
> @@ -855,9 +855,9 @@ static int prepare_keybuf(const u8 *key, unsigned int ksize,
> /* Generate a random length in range [0, max_len], but prefer smaller values */
> static unsigned int generate_random_length(unsigned int max_len)
> {
> - unsigned int len = prandom_u32() % (max_len + 1);
> + unsigned int len = prandom_u32_max(max_len + 1);
>
> - switch (prandom_u32() % 4) {
> + switch (prandom_u32_max(4)) {
> case 0:
> return len % 64;
> case 1:
> @@ -874,14 +874,14 @@ static void flip_random_bit(u8 *buf, size_t size)
> {
> size_t bitpos;
>
> - bitpos = prandom_u32() % (size * 8);
> + bitpos = prandom_u32_max(size * 8);
> buf[bitpos / 8] ^= 1 << (bitpos % 8);
> }
>
> /* Flip a random byte in the given nonempty data buffer */
> static void flip_random_byte(u8 *buf, size_t size)
> {
> - buf[prandom_u32() % size] ^= 0xff;
> + buf[prandom_u32_max(size)] ^= 0xff;
> }
>
> /* Sometimes make some random changes to the given nonempty data buffer */
> @@ -891,15 +891,15 @@ static void mutate_buffer(u8 *buf, size_t size)
> size_t i;
>
> /* Sometimes flip some bits */
> - if (prandom_u32() % 4 == 0) {
> - num_flips = min_t(size_t, 1 << (prandom_u32() % 8), size * 8);
> + if (prandom_u32_max(4) == 0) {
> + num_flips = min_t(size_t, 1 << prandom_u32_max(8), size * 8);
> for (i = 0; i < num_flips; i++)
> flip_random_bit(buf, size);
> }
>
> /* Sometimes flip some bytes */
> - if (prandom_u32() % 4 == 0) {
> - num_flips = min_t(size_t, 1 << (prandom_u32() % 8), size);
> + if (prandom_u32_max(4) == 0) {
> + num_flips = min_t(size_t, 1 << prandom_u32_max(8), size);
> for (i = 0; i < num_flips; i++)
> flip_random_byte(buf, size);
> }
> @@ -915,11 +915,11 @@ static void generate_random_bytes(u8 *buf, size_t count)
> if (count == 0)
> return;
>
> - switch (prandom_u32() % 8) { /* Choose a generation strategy */
> + switch (prandom_u32_max(8)) { /* Choose a generation strategy */
> case 0:
> case 1:
> /* All the same byte, plus optional mutations */
> - switch (prandom_u32() % 4) {
> + switch (prandom_u32_max(4)) {
> case 0:
> b = 0x00;
> break;
> @@ -959,24 +959,24 @@ static char *generate_random_sgl_divisions(struct test_sg_division *divs,
> unsigned int this_len;
> const char *flushtype_str;
>
> - if (div == &divs[max_divs - 1] || prandom_u32() % 2 == 0)
> + if (div == &divs[max_divs - 1] || prandom_u32_max(2) == 0)
> this_len = remaining;
> else
> - this_len = 1 + (prandom_u32() % remaining);
> + this_len = 1 + prandom_u32_max(remaining);
> div->proportion_of_total = this_len;
>
> - if (prandom_u32() % 4 == 0)
> - div->offset = (PAGE_SIZE - 128) + (prandom_u32() % 128);
> - else if (prandom_u32() % 2 == 0)
> - div->offset = prandom_u32() % 32;
> + if (prandom_u32_max(4) == 0)
> + div->offset = (PAGE_SIZE - 128) + prandom_u32_max(128);
> + else if (prandom_u32_max(2) == 0)
> + div->offset = prandom_u32_max(32);
> else
> - div->offset = prandom_u32() % PAGE_SIZE;
> - if (prandom_u32() % 8 == 0)
> + div->offset = prandom_u32_max(PAGE_SIZE);
> + if (prandom_u32_max(8) == 0)
> div->offset_relative_to_alignmask = true;
>
> div->flush_type = FLUSH_TYPE_NONE;
> if (gen_flushes) {
> - switch (prandom_u32() % 4) {
> + switch (prandom_u32_max(4)) {
> case 0:
> div->flush_type = FLUSH_TYPE_REIMPORT;
> break;
> @@ -988,7 +988,7 @@ static char *generate_random_sgl_divisions(struct test_sg_division *divs,
>
> if (div->flush_type != FLUSH_TYPE_NONE &&
> !(req_flags & CRYPTO_TFM_REQ_MAY_SLEEP) &&
> - prandom_u32() % 2 == 0)
> + prandom_u32_max(2) == 0)
> div->nosimd = true;
>
> switch (div->flush_type) {
> @@ -1035,7 +1035,7 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
>
> p += scnprintf(p, end - p, "random:");
>
> - switch (prandom_u32() % 4) {
> + switch (prandom_u32_max(4)) {
> case 0:
> case 1:
> cfg->inplace_mode = OUT_OF_PLACE;
> @@ -1050,12 +1050,12 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
> break;
> }
>
> - if (prandom_u32() % 2 == 0) {
> + if (prandom_u32_max(2) == 0) {
> cfg->req_flags |= CRYPTO_TFM_REQ_MAY_SLEEP;
> p += scnprintf(p, end - p, " may_sleep");
> }
>
> - switch (prandom_u32() % 4) {
> + switch (prandom_u32_max(4)) {
> case 0:
> cfg->finalization_type = FINALIZATION_TYPE_FINAL;
> p += scnprintf(p, end - p, " use_final");
> @@ -1071,7 +1071,7 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
> }
>
> if (!(cfg->req_flags & CRYPTO_TFM_REQ_MAY_SLEEP) &&
> - prandom_u32() % 2 == 0) {
> + prandom_u32_max(2) == 0) {
> cfg->nosimd = true;
> p += scnprintf(p, end - p, " nosimd");
> }
> @@ -1084,7 +1084,7 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
> cfg->req_flags);
> p += scnprintf(p, end - p, "]");
>
> - if (cfg->inplace_mode == OUT_OF_PLACE && prandom_u32() % 2 == 0) {
> + if (cfg->inplace_mode == OUT_OF_PLACE && prandom_u32_max(2) == 0) {
> p += scnprintf(p, end - p, " dst_divs=[");
> p = generate_random_sgl_divisions(cfg->dst_divs,
> ARRAY_SIZE(cfg->dst_divs),
> @@ -1093,13 +1093,13 @@ static void generate_random_testvec_config(struct testvec_config *cfg,
> p += scnprintf(p, end - p, "]");
> }
>
> - if (prandom_u32() % 2 == 0) {
> - cfg->iv_offset = 1 + (prandom_u32() % MAX_ALGAPI_ALIGNMASK);
> + if (prandom_u32_max(2) == 0) {
> + cfg->iv_offset = 1 + prandom_u32_max(MAX_ALGAPI_ALIGNMASK);
> p += scnprintf(p, end - p, " iv_offset=%u", cfg->iv_offset);
> }
>
> - if (prandom_u32() % 2 == 0) {
> - cfg->key_offset = 1 + (prandom_u32() % MAX_ALGAPI_ALIGNMASK);
> + if (prandom_u32_max(2) == 0) {
> + cfg->key_offset = 1 + prandom_u32_max(MAX_ALGAPI_ALIGNMASK);
> p += scnprintf(p, end - p, " key_offset=%u", cfg->key_offset);
> }
>
> @@ -1652,8 +1652,8 @@ static void generate_random_hash_testvec(struct shash_desc *desc,
> vec->ksize = 0;
> if (maxkeysize) {
> vec->ksize = maxkeysize;
> - if (prandom_u32() % 4 == 0)
> - vec->ksize = 1 + (prandom_u32() % maxkeysize);
> + if (prandom_u32_max(4) == 0)
> + vec->ksize = 1 + prandom_u32_max(maxkeysize);
> generate_random_bytes((u8 *)vec->key, vec->ksize);
>
> vec->setkey_error = crypto_shash_setkey(desc->tfm, vec->key,
> @@ -2218,13 +2218,13 @@ static void mutate_aead_message(struct aead_testvec *vec, bool aad_iv,
> const unsigned int aad_tail_size = aad_iv ? ivsize : 0;
> const unsigned int authsize = vec->clen - vec->plen;
>
> - if (prandom_u32() % 2 == 0 && vec->alen > aad_tail_size) {
> + if (prandom_u32_max(2) == 0 && vec->alen > aad_tail_size) {
> /* Mutate the AAD */
> flip_random_bit((u8 *)vec->assoc, vec->alen - aad_tail_size);
> - if (prandom_u32() % 2 == 0)
> + if (prandom_u32_max(2) == 0)
> return;
> }
> - if (prandom_u32() % 2 == 0) {
> + if (prandom_u32_max(2) == 0) {
> /* Mutate auth tag (assuming it's at the end of ciphertext) */
> flip_random_bit((u8 *)vec->ctext + vec->plen, authsize);
> } else {
> @@ -2249,7 +2249,7 @@ static void generate_aead_message(struct aead_request *req,
> const unsigned int ivsize = crypto_aead_ivsize(tfm);
> const unsigned int authsize = vec->clen - vec->plen;
> const bool inauthentic = (authsize >= MIN_COLLISION_FREE_AUTHSIZE) &&
> - (prefer_inauthentic || prandom_u32() % 4 == 0);
> + (prefer_inauthentic || prandom_u32_max(4) == 0);
>
> /* Generate the AAD. */
> generate_random_bytes((u8 *)vec->assoc, vec->alen);
> @@ -2257,7 +2257,7 @@ static void generate_aead_message(struct aead_request *req,
> /* Avoid implementation-defined behavior. */
> memcpy((u8 *)vec->assoc + vec->alen - ivsize, vec->iv, ivsize);
>
> - if (inauthentic && prandom_u32() % 2 == 0) {
> + if (inauthentic && prandom_u32_max(2) == 0) {
> /* Generate a random ciphertext. */
> generate_random_bytes((u8 *)vec->ctext, vec->clen);
> } else {
> @@ -2321,8 +2321,8 @@ static void generate_random_aead_testvec(struct aead_request *req,
>
> /* Key: length in [0, maxkeysize], but usually choose maxkeysize */
> vec->klen = maxkeysize;
> - if (prandom_u32() % 4 == 0)
> - vec->klen = prandom_u32() % (maxkeysize + 1);
> + if (prandom_u32_max(4) == 0)
> + vec->klen = prandom_u32_max(maxkeysize + 1);
> generate_random_bytes((u8 *)vec->key, vec->klen);
> vec->setkey_error = crypto_aead_setkey(tfm, vec->key, vec->klen);
>
> @@ -2331,8 +2331,8 @@ static void generate_random_aead_testvec(struct aead_request *req,
>
> /* Tag length: in [0, maxauthsize], but usually choose maxauthsize */
> authsize = maxauthsize;
> - if (prandom_u32() % 4 == 0)
> - authsize = prandom_u32() % (maxauthsize + 1);
> + if (prandom_u32_max(4) == 0)
> + authsize = prandom_u32_max(maxauthsize + 1);
> if (prefer_inauthentic && authsize < MIN_COLLISION_FREE_AUTHSIZE)
> authsize = MIN_COLLISION_FREE_AUTHSIZE;
> if (WARN_ON(authsize > maxdatasize))
> @@ -2342,7 +2342,7 @@ static void generate_random_aead_testvec(struct aead_request *req,
>
> /* AAD, plaintext, and ciphertext lengths */
> total_len = generate_random_length(maxdatasize);
> - if (prandom_u32() % 4 == 0)
> + if (prandom_u32_max(4) == 0)
> vec->alen = 0;
> else
> vec->alen = generate_random_length(total_len);
> @@ -2958,8 +2958,8 @@ static void generate_random_cipher_testvec(struct skcipher_request *req,
>
> /* Key: length in [0, maxkeysize], but usually choose maxkeysize */
> vec->klen = maxkeysize;
> - if (prandom_u32() % 4 == 0)
> - vec->klen = prandom_u32() % (maxkeysize + 1);
> + if (prandom_u32_max(4) == 0)
> + vec->klen = prandom_u32_max(maxkeysize + 1);
> generate_random_bytes((u8 *)vec->key, vec->klen);
> vec->setkey_error = crypto_skcipher_setkey(tfm, vec->key, vec->klen);
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> index cd75b0ca2555..845023c14eb3 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
> @@ -2424,7 +2424,7 @@ gen8_dispatch_bsd_engine(struct drm_i915_private *dev_priv,
> /* Check whether the file_priv has already selected one ring. */
> if ((int)file_priv->bsd_engine < 0)
> file_priv->bsd_engine =
> - get_random_int() % num_vcs_engines(dev_priv);
> + prandom_u32_max(num_vcs_engines(dev_priv));
>
> return file_priv->bsd_engine;
> }
> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
> index be317f2665a9..d460935e89eb 100644
> --- a/drivers/infiniband/core/cma.c
> +++ b/drivers/infiniband/core/cma.c
> @@ -3759,7 +3759,7 @@ static int cma_alloc_any_port(enum rdma_ucm_port_space ps,
>
> inet_get_local_port_range(net, &low, &high);
> remaining = (high - low) + 1;
> - rover = prandom_u32() % remaining + low;
> + rover = prandom_u32_max(remaining) + low;
> retry:
> if (last_used_port != rover) {
> struct rdma_bind_list *bind_list;
> diff --git a/drivers/infiniband/hw/cxgb4/id_table.c b/drivers/infiniband/hw/cxgb4/id_table.c
> index f64e7e02b129..280d61466855 100644
> --- a/drivers/infiniband/hw/cxgb4/id_table.c
> +++ b/drivers/infiniband/hw/cxgb4/id_table.c
> @@ -54,7 +54,7 @@ u32 c4iw_id_alloc(struct c4iw_id_table *alloc)
>
> if (obj < alloc->max) {
> if (alloc->flags & C4IW_ID_TABLE_F_RANDOM)
> - alloc->last += prandom_u32() % RANDOM_SKIP;
> + alloc->last += prandom_u32_max(RANDOM_SKIP);
> else
> alloc->last = obj + 1;
> if (alloc->last >= alloc->max)
> @@ -85,7 +85,7 @@ int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num,
> alloc->start = start;
> alloc->flags = flags;
> if (flags & C4IW_ID_TABLE_F_RANDOM)
> - alloc->last = prandom_u32() % RANDOM_SKIP;
> + alloc->last = prandom_u32_max(RANDOM_SKIP);
> else
> alloc->last = 0;
> alloc->max = num;
> diff --git a/drivers/infiniband/hw/hns/hns_roce_ah.c b/drivers/infiniband/hw/hns/hns_roce_ah.c
> index 492b122d0521..480c062dd04f 100644
> --- a/drivers/infiniband/hw/hns/hns_roce_ah.c
> +++ b/drivers/infiniband/hw/hns/hns_roce_ah.c
> @@ -41,9 +41,8 @@ static inline u16 get_ah_udp_sport(const struct rdma_ah_attr *ah_attr)
> u16 sport;
>
> if (!fl)
> - sport = get_random_u32() %
> - (IB_ROCE_UDP_ENCAP_VALID_PORT_MAX + 1 -
> - IB_ROCE_UDP_ENCAP_VALID_PORT_MIN) +
> + sport = prandom_u32_max(IB_ROCE_UDP_ENCAP_VALID_PORT_MAX + 1 -
> + IB_ROCE_UDP_ENCAP_VALID_PORT_MIN) +
> IB_ROCE_UDP_ENCAP_VALID_PORT_MIN;
> else
> sport = rdma_flow_label_to_udp_sport(fl);
> diff --git a/drivers/infiniband/ulp/rtrs/rtrs-clt.c b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> index 449904dac0a9..e2a89d7f52df 100644
> --- a/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> +++ b/drivers/infiniband/ulp/rtrs/rtrs-clt.c
> @@ -1511,8 +1511,7 @@ static void rtrs_clt_err_recovery_work(struct work_struct *work)
> rtrs_clt_stop_and_destroy_conns(clt_path);
> queue_delayed_work(rtrs_wq, &clt_path->reconnect_dwork,
> msecs_to_jiffies(delay_ms +
> - prandom_u32() %
> - RTRS_RECONNECT_SEED));
> + prandom_u32_max(RTRS_RECONNECT_SEED)));
> }
>
> static struct rtrs_clt_path *alloc_path(struct rtrs_clt_sess *clt,
> diff --git a/drivers/media/test-drivers/vivid/vivid-touch-cap.c b/drivers/media/test-drivers/vivid/vivid-touch-cap.c
> index 64e3e4cb30c2..792660a85bc1 100644
> --- a/drivers/media/test-drivers/vivid/vivid-touch-cap.c
> +++ b/drivers/media/test-drivers/vivid/vivid-touch-cap.c
> @@ -221,7 +221,7 @@ static void vivid_fill_buff_noise(__s16 *tch_buf, int size)
>
> static inline int get_random_pressure(void)
> {
> - return get_random_int() % VIVID_PRESSURE_LIMIT;
> + return prandom_u32_max(VIVID_PRESSURE_LIMIT);
> }
>
> static void vivid_tch_buf_set(struct v4l2_pix_format *f,
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index ef53a2578824..95fa8fb1d45f 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -97,8 +97,8 @@ static void mmc_should_fail_request(struct mmc_host *host,
> !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
> return;
>
> - data->error = data_errors[prandom_u32() % ARRAY_SIZE(data_errors)];
> - data->bytes_xfered = (prandom_u32() % (data->bytes_xfered >> 9)) << 9;
> + data->error = data_errors[prandom_u32_max(ARRAY_SIZE(data_errors))];
> + data->bytes_xfered = prandom_u32_max(data->bytes_xfered >> 9) << 9;
> }
>
> #else /* CONFIG_FAIL_MMC_REQUEST */
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 581614196a84..c78bbc22e0d1 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1858,7 +1858,7 @@ static void dw_mci_start_fault_timer(struct dw_mci *host)
> * Try to inject the error at random points during the data transfer.
> */
> hrtimer_start(&host->fault_timer,
> - ms_to_ktime(prandom_u32() % 25),
> + ms_to_ktime(prandom_u32_max(25)),
> HRTIMER_MODE_REL);
> }
>
> diff --git a/drivers/mtd/nand/raw/nandsim.c b/drivers/mtd/nand/raw/nandsim.c
> index 24beade95c7f..50bcf745e816 100644
> --- a/drivers/mtd/nand/raw/nandsim.c
> +++ b/drivers/mtd/nand/raw/nandsim.c
> @@ -1405,9 +1405,9 @@ static void ns_do_bit_flips(struct nandsim *ns, int num)
> if (bitflips && prandom_u32() < (1 << 22)) {
> int flips = 1;
> if (bitflips > 1)
> - flips = (prandom_u32() % (int) bitflips) + 1;
> + flips = prandom_u32_max(bitflips) + 1;
> while (flips--) {
> - int pos = prandom_u32() % (num * 8);
> + int pos = prandom_u32_max(num * 8);
> ns->buf.byte[pos / 8] ^= (1 << (pos % 8));
> NS_WARN("read_page: flipping bit %d in page %d "
> "reading from %d ecc: corrected=%u failed=%u\n",
> diff --git a/drivers/mtd/tests/mtd_nandecctest.c b/drivers/mtd/tests/mtd_nandecctest.c
> index c4f271314f52..1c7201b0f372 100644
> --- a/drivers/mtd/tests/mtd_nandecctest.c
> +++ b/drivers/mtd/tests/mtd_nandecctest.c
> @@ -47,7 +47,7 @@ struct nand_ecc_test {
> static void single_bit_error_data(void *error_data, void *correct_data,
> size_t size)
> {
> - unsigned int offset = prandom_u32() % (size * BITS_PER_BYTE);
> + unsigned int offset = prandom_u32_max(size * BITS_PER_BYTE);
>
> memcpy(error_data, correct_data, size);
> __change_bit_le(offset, error_data);
> @@ -58,9 +58,9 @@ static void double_bit_error_data(void *error_data, void *correct_data,
> {
> unsigned int offset[2];
>
> - offset[0] = prandom_u32() % (size * BITS_PER_BYTE);
> + offset[0] = prandom_u32_max(size * BITS_PER_BYTE);
> do {
> - offset[1] = prandom_u32() % (size * BITS_PER_BYTE);
> + offset[1] = prandom_u32_max(size * BITS_PER_BYTE);
> } while (offset[0] == offset[1]);
>
> memcpy(error_data, correct_data, size);
> @@ -71,7 +71,7 @@ static void double_bit_error_data(void *error_data, void *correct_data,
>
> static unsigned int random_ecc_bit(size_t size)
> {
> - unsigned int offset = prandom_u32() % (3 * BITS_PER_BYTE);
> + unsigned int offset = prandom_u32_max(3 * BITS_PER_BYTE);
>
> if (size == 256) {
> /*
> @@ -79,7 +79,7 @@ static unsigned int random_ecc_bit(size_t size)
> * and 17th bit) in ECC code for 256 byte data block
> */
> while (offset == 16 || offset == 17)
> - offset = prandom_u32() % (3 * BITS_PER_BYTE);
> + offset = prandom_u32_max(3 * BITS_PER_BYTE);
> }
>
> return offset;
> diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
> index 31d427ee191a..908d0e088557 100644
> --- a/drivers/mtd/ubi/debug.c
> +++ b/drivers/mtd/ubi/debug.c
> @@ -590,7 +590,7 @@ int ubi_dbg_power_cut(struct ubi_device *ubi, int caller)
>
> if (ubi->dbg.power_cut_max > ubi->dbg.power_cut_min) {
> range = ubi->dbg.power_cut_max - ubi->dbg.power_cut_min;
> - ubi->dbg.power_cut_counter += prandom_u32() % range;
> + ubi->dbg.power_cut_counter += prandom_u32_max(range);
> }
> return 0;
> }
> diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
> index 539992dad8ba..a4256087ac82 100644
> --- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
> +++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
> @@ -919,8 +919,8 @@ static int csk_wait_memory(struct chtls_dev *cdev,
> current_timeo = *timeo_p;
> noblock = (*timeo_p ? false : true);
> if (csk_mem_free(cdev, sk)) {
> - current_timeo = (prandom_u32() % (HZ / 5)) + 2;
> - vm_wait = (prandom_u32() % (HZ / 5)) + 2;
> + current_timeo = prandom_u32_max(HZ / 5) + 2;
> + vm_wait = prandom_u32_max(HZ / 5) + 2;
> }
>
> add_wait_queue(sk_sleep(sk), &wait);
> diff --git a/drivers/net/hamradio/baycom_epp.c b/drivers/net/hamradio/baycom_epp.c
> index 3e69079ed694..7df78a721b04 100644
> --- a/drivers/net/hamradio/baycom_epp.c
> +++ b/drivers/net/hamradio/baycom_epp.c
> @@ -438,7 +438,7 @@ static int transmit(struct baycom_state *bc, int cnt, unsigned char stat)
> if ((--bc->hdlctx.slotcnt) > 0)
> return 0;
> bc->hdlctx.slotcnt = bc->ch_params.slottime;
> - if ((prandom_u32() % 256) > bc->ch_params.ppersist)
> + if (prandom_u32_max(256) > bc->ch_params.ppersist)
> return 0;
> }
> }
> diff --git a/drivers/net/hamradio/hdlcdrv.c b/drivers/net/hamradio/hdlcdrv.c
> index 8297411e87ea..360d041a62c4 100644
> --- a/drivers/net/hamradio/hdlcdrv.c
> +++ b/drivers/net/hamradio/hdlcdrv.c
> @@ -377,7 +377,7 @@ void hdlcdrv_arbitrate(struct net_device *dev, struct hdlcdrv_state *s)
> if ((--s->hdlctx.slotcnt) > 0)
> return;
> s->hdlctx.slotcnt = s->ch_params.slottime;
> - if ((prandom_u32() % 256) > s->ch_params.ppersist)
> + if (prandom_u32_max(256) > s->ch_params.ppersist)
> return;
> start_tx(dev, s);
> }
> diff --git a/drivers/net/hamradio/yam.c b/drivers/net/hamradio/yam.c
> index 980f2be32f05..97a6cc5c7ae8 100644
> --- a/drivers/net/hamradio/yam.c
> +++ b/drivers/net/hamradio/yam.c
> @@ -626,7 +626,7 @@ static void yam_arbitrate(struct net_device *dev)
> yp->slotcnt = yp->slot / 10;
>
> /* is random > persist ? */
> - if ((prandom_u32() % 256) > yp->pers)
> + if (prandom_u32_max(256) > yp->pers)
> return;
>
> yam_start_tx(dev, yp);
> diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
> index 59fe356942b5..2a7108361246 100644
> --- a/drivers/net/phy/at803x.c
> +++ b/drivers/net/phy/at803x.c
> @@ -1732,7 +1732,7 @@ static int qca808x_phy_fast_retrain_config(struct phy_device *phydev)
>
> static int qca808x_phy_ms_random_seed_set(struct phy_device *phydev)
> {
> - u16 seed_value = (prandom_u32() % QCA808X_MASTER_SLAVE_SEED_RANGE);
> + u16 seed_value = prandom_u32_max(QCA808X_MASTER_SLAVE_SEED_RANGE);
>
> return at803x_debug_reg_mask(phydev, QCA808X_PHY_DEBUG_LOCAL_SEED,
> QCA808X_MASTER_SLAVE_SEED_CFG,
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
> index 479041f070f9..10d9d9c63b28 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c
> @@ -1128,7 +1128,7 @@ static void brcmf_p2p_afx_handler(struct work_struct *work)
> if (afx_hdl->is_listen && afx_hdl->my_listen_chan)
> /* 100ms ~ 300ms */
> err = brcmf_p2p_discover_listen(p2p, afx_hdl->my_listen_chan,
> - 100 * (1 + prandom_u32() % 3));
> + 100 * (1 + prandom_u32_max(3)));
> else
> err = brcmf_p2p_act_frm_search(p2p, afx_hdl->peer_listen_chan);
>
> diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c b/drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c
> index ed586e6d7d64..de0c545d50fd 100644
> --- a/drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c
> +++ b/drivers/net/wireless/intel/iwlwifi/mvm/mac-ctxt.c
> @@ -1099,7 +1099,7 @@ static void iwl_mvm_mac_ctxt_cmd_fill_ap(struct iwl_mvm *mvm,
> iwl_mvm_mac_ap_iterator, &data);
>
> if (data.beacon_device_ts) {
> - u32 rand = (prandom_u32() % (64 - 36)) + 36;
> + u32 rand = prandom_u32_max(64 - 36) + 36;
> mvmvif->ap_beacon_time = data.beacon_device_ts +
> ieee80211_tu_to_usec(data.beacon_int * rand /
> 100);
> diff --git a/drivers/scsi/fcoe/fcoe_ctlr.c b/drivers/scsi/fcoe/fcoe_ctlr.c
> index 39e16eab47aa..ddc048069af2 100644
> --- a/drivers/scsi/fcoe/fcoe_ctlr.c
> +++ b/drivers/scsi/fcoe/fcoe_ctlr.c
> @@ -2233,7 +2233,7 @@ static void fcoe_ctlr_vn_restart(struct fcoe_ctlr *fip)
>
> if (fip->probe_tries < FIP_VN_RLIM_COUNT) {
> fip->probe_tries++;
> - wait = prandom_u32() % FIP_VN_PROBE_WAIT;
> + wait = prandom_u32_max(FIP_VN_PROBE_WAIT);
> } else
> wait = FIP_VN_RLIM_INT;
> mod_timer(&fip->timer, jiffies + msecs_to_jiffies(wait));
> @@ -3125,7 +3125,7 @@ static void fcoe_ctlr_vn_timeout(struct fcoe_ctlr *fip)
> fcoe_all_vn2vn, 0);
> fip->port_ka_time = jiffies +
> msecs_to_jiffies(FIP_VN_BEACON_INT +
> - (prandom_u32() % FIP_VN_BEACON_FUZZ));
> + prandom_u32_max(FIP_VN_BEACON_FUZZ));
> }
> if (time_before(fip->port_ka_time, next_time))
> next_time = fip->port_ka_time;
> diff --git a/drivers/scsi/qedi/qedi_main.c b/drivers/scsi/qedi/qedi_main.c
> index cecfb2cb4c7b..df2fe7bd26d1 100644
> --- a/drivers/scsi/qedi/qedi_main.c
> +++ b/drivers/scsi/qedi/qedi_main.c
> @@ -618,7 +618,7 @@ static int qedi_cm_alloc_mem(struct qedi_ctx *qedi)
> sizeof(struct qedi_endpoint *)), GFP_KERNEL);
> if (!qedi->ep_tbl)
> return -ENOMEM;
> - port_id = prandom_u32() % QEDI_LOCAL_PORT_RANGE;
> + port_id = prandom_u32_max(QEDI_LOCAL_PORT_RANGE);
> if (qedi_init_id_tbl(&qedi->lcl_port_tbl, QEDI_LOCAL_PORT_RANGE,
> QEDI_LOCAL_PORT_MIN, port_id)) {
> qedi_cm_free_mem(qedi);
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 42351d7a0dd6..f0c6e7e7b92b 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -362,7 +362,7 @@ static int ceph_fill_fragtree(struct inode *inode,
> if (nsplits != ci->i_fragtree_nsplits) {
> update = true;
> } else if (nsplits) {
> - i = prandom_u32() % nsplits;
> + i = prandom_u32_max(nsplits);
> id = le32_to_cpu(fragtree->splits[i].frag);
> if (!__ceph_find_frag(ci, id))
> update = true;
> diff --git a/fs/ceph/mdsmap.c b/fs/ceph/mdsmap.c
> index 8d0a6d2c2da4..3fbabc98e1f7 100644
> --- a/fs/ceph/mdsmap.c
> +++ b/fs/ceph/mdsmap.c
> @@ -29,7 +29,7 @@ static int __mdsmap_get_random_mds(struct ceph_mdsmap *m, bool ignore_laggy)
> return -1;
>
> /* pick */
> - n = prandom_u32() % n;
> + n = prandom_u32_max(n);
> for (j = 0, i = 0; i < m->possible_max_rank; i++) {
> if (CEPH_MDS_IS_READY(i, ignore_laggy))
> j++;
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 9a66abcca1a8..4af351320075 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -3811,8 +3811,7 @@ static int ext4_lazyinit_thread(void *arg)
> }
> if (!progress) {
> elr->lr_next_sched = jiffies +
> - (prandom_u32()
> - % (EXT4_DEF_LI_MAX_START_DELAY * HZ));
> + prandom_u32_max(EXT4_DEF_LI_MAX_START_DELAY * HZ);
> }
> if (time_before(elr->lr_next_sched, next_wakeup))
> next_wakeup = elr->lr_next_sched;
> @@ -3959,8 +3958,8 @@ static struct ext4_li_request *ext4_li_request_new(struct super_block *sb,
> * spread the inode table initialization requests
> * better.
> */
> - elr->lr_next_sched = jiffies + (prandom_u32() %
> - (EXT4_DEF_LI_MAX_START_DELAY * HZ));
> + elr->lr_next_sched = jiffies + prandom_u32_max(
> + EXT4_DEF_LI_MAX_START_DELAY * HZ);
> return elr;
> }
>
> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
> index 6da21d405ce1..2c5fd1db3a3e 100644
> --- a/fs/f2fs/gc.c
> +++ b/fs/f2fs/gc.c
> @@ -285,7 +285,7 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
>
> /* let's select beginning hot/small space first in no_heap mode*/
> if (f2fs_need_rand_seg(sbi))
> - p->offset = prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec);
> + p->offset = prandom_u32_max(MAIN_SECS(sbi) * sbi->segs_per_sec);
> else if (test_opt(sbi, NOHEAP) &&
> (type == CURSEG_HOT_DATA || IS_NODESEG(type)))
> p->offset = 0;
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index 0de21f82d7bc..507f77f839f3 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -2535,7 +2535,7 @@ static unsigned int __get_next_segno(struct f2fs_sb_info *sbi, int type)
>
> sanity_check_seg_type(sbi, seg_type);
> if (f2fs_need_rand_seg(sbi))
> - return prandom_u32() % (MAIN_SECS(sbi) * sbi->segs_per_sec);
> + return prandom_u32_max(MAIN_SECS(sbi) * sbi->segs_per_sec);
>
> /* if segs_per_sec is large than 1, we need to keep original policy. */
> if (__is_large_section(sbi))
> @@ -2589,7 +2589,7 @@ static void new_curseg(struct f2fs_sb_info *sbi, int type, bool new_sec)
> curseg->alloc_type = LFS;
> if (F2FS_OPTION(sbi).fs_mode == FS_MODE_FRAGMENT_BLK)
> curseg->fragment_remained_chunk =
> - prandom_u32() % sbi->max_fragment_chunk + 1;
> + prandom_u32_max(sbi->max_fragment_chunk) + 1;
> }
>
> static int __next_free_blkoff(struct f2fs_sb_info *sbi,
> @@ -2626,9 +2626,9 @@ static void __refresh_next_blkoff(struct f2fs_sb_info *sbi,
> /* To allocate block chunks in different sizes, use random number */
> if (--seg->fragment_remained_chunk <= 0) {
> seg->fragment_remained_chunk =
> - prandom_u32() % sbi->max_fragment_chunk + 1;
> + prandom_u32_max(sbi->max_fragment_chunk) + 1;
> seg->next_blkoff +=
> - prandom_u32() % sbi->max_fragment_hole + 1;
> + prandom_u32_max(sbi->max_fragment_hole) + 1;
> }
> }
> }
> diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
> index fc718f6178f2..f4d3b568aa64 100644
> --- a/fs/ubifs/debug.c
> +++ b/fs/ubifs/debug.c
> @@ -2467,7 +2467,7 @@ int dbg_check_nondata_nodes_order(struct ubifs_info *c, struct list_head *head)
>
> static inline int chance(unsigned int n, unsigned int out_of)
> {
> - return !!((prandom_u32() % out_of) + 1 <= n);
> + return !!(prandom_u32_max(out_of) + 1 <= n);
>
> }
>
> @@ -2485,13 +2485,13 @@ static int power_cut_emulated(struct ubifs_info *c, int lnum, int write)
> if (chance(1, 2)) {
> d->pc_delay = 1;
> /* Fail within 1 minute */
> - delay = prandom_u32() % 60000;
> + delay = prandom_u32_max(60000);
> d->pc_timeout = jiffies;
> d->pc_timeout += msecs_to_jiffies(delay);
> ubifs_warn(c, "failing after %lums", delay);
> } else {
> d->pc_delay = 2;
> - delay = prandom_u32() % 10000;
> + delay = prandom_u32_max(10000);
> /* Fail within 10000 operations */
> d->pc_cnt_max = delay;
> ubifs_warn(c, "failing after %lu calls", delay);
> @@ -2571,7 +2571,7 @@ static int corrupt_data(const struct ubifs_info *c, const void *buf,
> unsigned int from, to, ffs = chance(1, 2);
> unsigned char *p = (void *)buf;
>
> - from = prandom_u32() % len;
> + from = prandom_u32_max(len);
> /* Corruption span max to end of write unit */
> to = min(len, ALIGN(from + 1, c->max_write_size));
>
> diff --git a/fs/ubifs/lpt_commit.c b/fs/ubifs/lpt_commit.c
> index d76a19e460cd..cd4d5726a78d 100644
> --- a/fs/ubifs/lpt_commit.c
> +++ b/fs/ubifs/lpt_commit.c
> @@ -1977,21 +1977,21 @@ static int dbg_populate_lsave(struct ubifs_info *c)
> c->lsave[i] = c->main_first;
>
> list_for_each_entry(lprops, &c->empty_list, list)
> - c->lsave[prandom_u32() % c->lsave_cnt] = lprops->lnum;
> + c->lsave[prandom_u32_max(c->lsave_cnt)] = lprops->lnum;
> list_for_each_entry(lprops, &c->freeable_list, list)
> - c->lsave[prandom_u32() % c->lsave_cnt] = lprops->lnum;
> + c->lsave[prandom_u32_max(c->lsave_cnt)] = lprops->lnum;
> list_for_each_entry(lprops, &c->frdi_idx_list, list)
> - c->lsave[prandom_u32() % c->lsave_cnt] = lprops->lnum;
> + c->lsave[prandom_u32_max(c->lsave_cnt)] = lprops->lnum;
>
> heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
> for (i = 0; i < heap->cnt; i++)
> - c->lsave[prandom_u32() % c->lsave_cnt] = heap->arr[i]->lnum;
> + c->lsave[prandom_u32_max(c->lsave_cnt)] = heap->arr[i]->lnum;
> heap = &c->lpt_heap[LPROPS_DIRTY - 1];
> for (i = 0; i < heap->cnt; i++)
> - c->lsave[prandom_u32() % c->lsave_cnt] = heap->arr[i]->lnum;
> + c->lsave[prandom_u32_max(c->lsave_cnt)] = heap->arr[i]->lnum;
> heap = &c->lpt_heap[LPROPS_FREE - 1];
> for (i = 0; i < heap->cnt; i++)
> - c->lsave[prandom_u32() % c->lsave_cnt] = heap->arr[i]->lnum;
> + c->lsave[prandom_u32_max(c->lsave_cnt)] = heap->arr[i]->lnum;
>
> return 1;
> }
> diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
> index 296faa41d81d..7db588ed0be5 100644
> --- a/fs/xfs/xfs_error.c
> +++ b/fs/xfs/xfs_error.c
> @@ -274,7 +274,7 @@ xfs_errortag_test(
>
> ASSERT(error_tag < XFS_ERRTAG_MAX);
> randfactor = mp->m_errortag[error_tag];
> - if (!randfactor || prandom_u32() % randfactor)
> + if (!randfactor || prandom_u32_max(randfactor))
> return false;
>
> xfs_warn_ratelimited(mp,
> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
> index 3d9eb3ae334c..ade6b03b1d9b 100644
> --- a/kernel/bpf/core.c
> +++ b/kernel/bpf/core.c
> @@ -1027,7 +1027,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
> hdr->size = size;
> hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
> PAGE_SIZE - sizeof(*hdr));
> - start = (get_random_int() % hole) & ~(alignment - 1);
> + start = prandom_u32_max(hole) & ~(alignment - 1);
>
> /* Leave a random number of instructions before BPF code. */
> *image_ptr = &hdr->image[start];
> @@ -1089,7 +1089,7 @@ bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
>
> hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
> BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
> - start = (get_random_int() % hole) & ~(alignment - 1);
> + start = prandom_u32_max(hole) & ~(alignment - 1);
>
> *image_ptr = &ro_header->image[start];
> *rw_image = &(*rw_header)->image[start];
> diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
> index 353004155d65..43efb2a04160 100644
> --- a/kernel/locking/test-ww_mutex.c
> +++ b/kernel/locking/test-ww_mutex.c
> @@ -399,7 +399,7 @@ static int *get_random_order(int count)
> order[n] = n;
>
> for (n = count - 1; n > 1; n--) {
> - r = get_random_int() % (n + 1);
> + r = prandom_u32_max(n + 1);
> if (r != n) {
> tmp = order[n];
> order[n] = order[r];
> @@ -538,7 +538,7 @@ static void stress_one_work(struct work_struct *work)
> {
> struct stress *stress = container_of(work, typeof(*stress), work);
> const int nlocks = stress->nlocks;
> - struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks);
> + struct ww_mutex *lock = stress->locks + prandom_u32_max(nlocks);
> int err;
>
> do {
> diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> index cee5da1e54c4..8058bec87ace 100644
> --- a/kernel/time/clocksource.c
> +++ b/kernel/time/clocksource.c
> @@ -310,7 +310,7 @@ static void clocksource_verify_choose_cpus(void)
> * CPUs that are currently online.
> */
> for (i = 1; i < n; i++) {
> - cpu = prandom_u32() % nr_cpu_ids;
> + cpu = prandom_u32_max(nr_cpu_ids);
> cpu = cpumask_next(cpu - 1, cpu_online_mask);
> if (cpu >= nr_cpu_ids)
> cpu = cpumask_first(cpu_online_mask);
> diff --git a/lib/cmdline_kunit.c b/lib/cmdline_kunit.c
> index a72a2c16066e..e6a31c927b06 100644
> --- a/lib/cmdline_kunit.c
> +++ b/lib/cmdline_kunit.c
> @@ -76,7 +76,7 @@ static void cmdline_test_lead_int(struct kunit *test)
> int rc = cmdline_test_values[i];
> int offset;
>
> - sprintf(in, "%u%s", get_random_int() % 256, str);
> + sprintf(in, "%u%s", prandom_u32_max(256), str);
> /* Only first '-' after the number will advance the pointer */
> offset = strlen(in) - strlen(str) + !!(rc == 2);
> cmdline_do_one_test(test, in, rc, offset);
> @@ -94,7 +94,7 @@ static void cmdline_test_tail_int(struct kunit *test)
> int rc = strcmp(str, "") ? (strcmp(str, "-") ? 0 : 1) : 1;
> int offset;
>
> - sprintf(in, "%s%u", str, get_random_int() % 256);
> + sprintf(in, "%s%u", str, prandom_u32_max(256));
> /*
> * Only first and leading '-' not followed by integer
> * will advance the pointer.
> diff --git a/lib/fault-inject.c b/lib/fault-inject.c
> index 423784d9c058..96e092de5b72 100644
> --- a/lib/fault-inject.c
> +++ b/lib/fault-inject.c
> @@ -139,7 +139,7 @@ bool should_fail(struct fault_attr *attr, ssize_t size)
> return false;
> }
>
> - if (attr->probability <= prandom_u32() % 100)
> + if (attr->probability <= prandom_u32_max(100))
> return false;
>
> if (!fail_stacktrace(attr))
> diff --git a/lib/find_bit_benchmark.c b/lib/find_bit_benchmark.c
> index db904b57d4b8..1a6466c64bb6 100644
> --- a/lib/find_bit_benchmark.c
> +++ b/lib/find_bit_benchmark.c
> @@ -157,8 +157,8 @@ static int __init find_bit_test(void)
> bitmap_zero(bitmap2, BITMAP_LEN);
>
> while (nbits--) {
> - __set_bit(prandom_u32() % BITMAP_LEN, bitmap);
> - __set_bit(prandom_u32() % BITMAP_LEN, bitmap2);
> + __set_bit(prandom_u32_max(BITMAP_LEN), bitmap);
> + __set_bit(prandom_u32_max(BITMAP_LEN), bitmap2);
> }
>
> test_find_next_bit(bitmap, BITMAP_LEN);
> diff --git a/lib/reed_solomon/test_rslib.c b/lib/reed_solomon/test_rslib.c
> index d9d1c33aebda..6faf9c9a6215 100644
> --- a/lib/reed_solomon/test_rslib.c
> +++ b/lib/reed_solomon/test_rslib.c
> @@ -183,7 +183,7 @@ static int get_rcw_we(struct rs_control *rs, struct wspace *ws,
>
> do {
> /* Must not choose the same location twice */
> - errloc = prandom_u32() % len;
> + errloc = prandom_u32_max(len);
> } while (errlocs[errloc] != 0);
>
> errlocs[errloc] = 1;
> @@ -194,7 +194,7 @@ static int get_rcw_we(struct rs_control *rs, struct wspace *ws,
> for (i = 0; i < eras; i++) {
> do {
> /* Must not choose the same location twice */
> - errloc = prandom_u32() % len;
> + errloc = prandom_u32_max(len);
> } while (errlocs[errloc] != 0);
>
> derrlocs[i] = errloc;
> diff --git a/lib/sbitmap.c b/lib/sbitmap.c
> index 29eb0484215a..c4f04edf3ee9 100644
> --- a/lib/sbitmap.c
> +++ b/lib/sbitmap.c
> @@ -33,7 +33,7 @@ static inline unsigned update_alloc_hint_before_get(struct sbitmap *sb,
>
> hint = this_cpu_read(*sb->alloc_hint);
> if (unlikely(hint >= depth)) {
> - hint = depth ? prandom_u32() % depth : 0;
> + hint = depth ? prandom_u32_max(depth) : 0;
> this_cpu_write(*sb->alloc_hint, hint);
> }
>
> diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c
> index 437d8e6b7cb1..86fadd3ba08c 100644
> --- a/lib/test-string_helpers.c
> +++ b/lib/test-string_helpers.c
> @@ -587,7 +587,7 @@ static int __init test_string_helpers_init(void)
> for (i = 0; i < UNESCAPE_ALL_MASK + 1; i++)
> test_string_unescape("unescape", i, false);
> test_string_unescape("unescape inplace",
> - get_random_int() % (UNESCAPE_ANY + 1), true);
> + prandom_u32_max(UNESCAPE_ANY + 1), true);
>
> /* Without dictionary */
> for (i = 0; i < ESCAPE_ALL_MASK + 1; i++)
> diff --git a/lib/test_hexdump.c b/lib/test_hexdump.c
> index 5144899d3c6b..0927f44cd478 100644
> --- a/lib/test_hexdump.c
> +++ b/lib/test_hexdump.c
> @@ -149,7 +149,7 @@ static void __init test_hexdump(size_t len, int rowsize, int groupsize,
> static void __init test_hexdump_set(int rowsize, bool ascii)
> {
> size_t d = min_t(size_t, sizeof(data_b), rowsize);
> - size_t len = get_random_int() % d + 1;
> + size_t len = prandom_u32_max(d) + 1;
>
> test_hexdump(len, rowsize, 4, ascii);
> test_hexdump(len, rowsize, 2, ascii);
> @@ -208,11 +208,11 @@ static void __init test_hexdump_overflow(size_t buflen, size_t len,
> static void __init test_hexdump_overflow_set(size_t buflen, bool ascii)
> {
> unsigned int i = 0;
> - int rs = (get_random_int() % 2 + 1) * 16;
> + int rs = (prandom_u32_max(2) + 1) * 16;
>
> do {
> int gs = 1 << i;
> - size_t len = get_random_int() % rs + gs;
> + size_t len = prandom_u32_max(rs) + gs;
>
> test_hexdump_overflow(buflen, rounddown(len, gs), rs, gs, ascii);
> } while (i++ < 3);
> @@ -223,11 +223,11 @@ static int __init test_hexdump_init(void)
> unsigned int i;
> int rowsize;
>
> - rowsize = (get_random_int() % 2 + 1) * 16;
> + rowsize = (prandom_u32_max(2) + 1) * 16;
> for (i = 0; i < 16; i++)
> test_hexdump_set(rowsize, false);
>
> - rowsize = (get_random_int() % 2 + 1) * 16;
> + rowsize = (prandom_u32_max(2) + 1) * 16;
> for (i = 0; i < 16; i++)
> test_hexdump_set(rowsize, true);
>
> diff --git a/lib/test_kasan.c b/lib/test_kasan.c
> index 58c1b01ccfe2..7b4026623ace 100644
> --- a/lib/test_kasan.c
> +++ b/lib/test_kasan.c
> @@ -1269,7 +1269,7 @@ static void match_all_not_assigned(struct kunit *test)
> KASAN_TEST_NEEDS_CONFIG_OFF(test, CONFIG_KASAN_GENERIC);
>
> for (i = 0; i < 256; i++) {
> - size = (get_random_int() % 1024) + 1;
> + size = prandom_u32_max(1024) + 1;
> ptr = kmalloc(size, GFP_KERNEL);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
> @@ -1278,7 +1278,7 @@ static void match_all_not_assigned(struct kunit *test)
> }
>
> for (i = 0; i < 256; i++) {
> - order = (get_random_int() % 4) + 1;
> + order = prandom_u32_max(4) + 1;
> pages = alloc_pages(GFP_KERNEL, order);
> ptr = page_address(pages);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> @@ -1291,7 +1291,7 @@ static void match_all_not_assigned(struct kunit *test)
> return;
>
> for (i = 0; i < 256; i++) {
> - size = (get_random_int() % 1024) + 1;
> + size = prandom_u32_max(1024) + 1;
> ptr = vmalloc(size);
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ptr);
> KUNIT_EXPECT_GE(test, (u8)get_tag(ptr), (u8)KASAN_TAG_MIN);
> diff --git a/lib/test_list_sort.c b/lib/test_list_sort.c
> index ade7a1ea0c8e..19ff229b9c3a 100644
> --- a/lib/test_list_sort.c
> +++ b/lib/test_list_sort.c
> @@ -71,7 +71,7 @@ static void list_sort_test(struct kunit *test)
> KUNIT_ASSERT_NOT_ERR_OR_NULL(test, el);
>
> /* force some equivalencies */
> - el->value = prandom_u32() % (TEST_LIST_LEN / 3);
> + el->value = prandom_u32_max(TEST_LIST_LEN / 3);
> el->serial = i;
> el->poison1 = TEST_POISON1;
> el->poison2 = TEST_POISON2;
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 6a1597c92261..db04f95fe050 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2292,7 +2292,7 @@ int next_demotion_node(int node)
> * caching issue, which seems more complicated. So selecting
> * target node randomly seems better until now.
> */
> - index = get_random_int() % target_nr;
> + index = prandom_u32_max(target_nr);
> break;
> }
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 862dbd9af4f5..46ee52efeeef 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1911,7 +1911,7 @@ static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
> return false;
>
> freelist_count = oo_objects(s->oo);
> - pos = get_random_int() % freelist_count;
> + pos = prandom_u32_max(freelist_count);
>
> page_limit = slab->objects * s->size;
> start = fixup_red_left(s, slab_address(slab));
> diff --git a/net/ceph/mon_client.c b/net/ceph/mon_client.c
> index 6a6898ee4049..db60217f911b 100644
> --- a/net/ceph/mon_client.c
> +++ b/net/ceph/mon_client.c
> @@ -222,7 +222,7 @@ static void pick_new_mon(struct ceph_mon_client *monc)
> max--;
> }
>
> - n = prandom_u32() % max;
> + n = prandom_u32_max(max);
> if (o >= 0 && n >= o)
> n++;
>
> diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
> index 87b883c7bfd6..4e4f1e4bc265 100644
> --- a/net/ceph/osd_client.c
> +++ b/net/ceph/osd_client.c
> @@ -1479,7 +1479,7 @@ static bool target_should_be_paused(struct ceph_osd_client *osdc,
>
> static int pick_random_replica(const struct ceph_osds *acting)
> {
> - int i = prandom_u32() % acting->size;
> + int i = prandom_u32_max(acting->size);
>
> dout("%s picked osd%d, primary osd%d\n", __func__,
> acting->osds[i], acting->primary);
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index 78cc8fb68814..85d497cb58d8 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -111,7 +111,7 @@ static void neigh_cleanup_and_release(struct neighbour *neigh)
>
> unsigned long neigh_rand_reach_time(unsigned long base)
> {
> - return base ? (prandom_u32() % base) + (base >> 1) : 0;
> + return base ? prandom_u32_max(base) + (base >> 1) : 0;
> }
> EXPORT_SYMBOL(neigh_rand_reach_time);
>
> diff --git a/net/core/pktgen.c b/net/core/pktgen.c
> index 88906ba6d9a7..a13ee452429e 100644
> --- a/net/core/pktgen.c
> +++ b/net/core/pktgen.c
> @@ -2324,7 +2324,7 @@ static inline int f_pick(struct pktgen_dev *pkt_dev)
> pkt_dev->curfl = 0; /*reset */
> }
> } else {
> - flow = prandom_u32() % pkt_dev->cflows;
> + flow = prandom_u32_max(pkt_dev->cflows);
> pkt_dev->curfl = flow;
>
> if (pkt_dev->flows[flow].count > pkt_dev->lflow) {
> @@ -2380,10 +2380,9 @@ static void set_cur_queue_map(struct pktgen_dev *pkt_dev)
> else if (pkt_dev->queue_map_min <= pkt_dev->queue_map_max) {
> __u16 t;
> if (pkt_dev->flags & F_QUEUE_MAP_RND) {
> - t = prandom_u32() %
> - (pkt_dev->queue_map_max -
> - pkt_dev->queue_map_min + 1)
> - + pkt_dev->queue_map_min;
> + t = prandom_u32_max(pkt_dev->queue_map_max -
> + pkt_dev->queue_map_min + 1) +
> + pkt_dev->queue_map_min;
> } else {
> t = pkt_dev->cur_queue_map + 1;
> if (t > pkt_dev->queue_map_max)
> @@ -2412,7 +2411,7 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
> __u32 tmp;
>
> if (pkt_dev->flags & F_MACSRC_RND)
> - mc = prandom_u32() % pkt_dev->src_mac_count;
> + mc = prandom_u32_max(pkt_dev->src_mac_count);
> else {
> mc = pkt_dev->cur_src_mac_offset++;
> if (pkt_dev->cur_src_mac_offset >=
> @@ -2438,7 +2437,7 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
> __u32 tmp;
>
> if (pkt_dev->flags & F_MACDST_RND)
> - mc = prandom_u32() % pkt_dev->dst_mac_count;
> + mc = prandom_u32_max(pkt_dev->dst_mac_count);
>
> else {
> mc = pkt_dev->cur_dst_mac_offset++;
> @@ -2479,9 +2478,9 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
>
> if (pkt_dev->udp_src_min < pkt_dev->udp_src_max) {
> if (pkt_dev->flags & F_UDPSRC_RND)
> - pkt_dev->cur_udp_src = prandom_u32() %
> - (pkt_dev->udp_src_max - pkt_dev->udp_src_min)
> - + pkt_dev->udp_src_min;
> + pkt_dev->cur_udp_src = prandom_u32_max(
> + pkt_dev->udp_src_max - pkt_dev->udp_src_min) +
> + pkt_dev->udp_src_min;
>
> else {
> pkt_dev->cur_udp_src++;
> @@ -2492,9 +2491,9 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
>
> if (pkt_dev->udp_dst_min < pkt_dev->udp_dst_max) {
> if (pkt_dev->flags & F_UDPDST_RND) {
> - pkt_dev->cur_udp_dst = prandom_u32() %
> - (pkt_dev->udp_dst_max - pkt_dev->udp_dst_min)
> - + pkt_dev->udp_dst_min;
> + pkt_dev->cur_udp_dst = prandom_u32_max(
> + pkt_dev->udp_dst_max - pkt_dev->udp_dst_min) +
> + pkt_dev->udp_dst_min;
> } else {
> pkt_dev->cur_udp_dst++;
> if (pkt_dev->cur_udp_dst >= pkt_dev->udp_dst_max)
> @@ -2509,7 +2508,7 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
> if (imn < imx) {
> __u32 t;
> if (pkt_dev->flags & F_IPSRC_RND)
> - t = prandom_u32() % (imx - imn) + imn;
> + t = prandom_u32_max(imx - imn) + imn;
> else {
> t = ntohl(pkt_dev->cur_saddr);
> t++;
> @@ -2531,8 +2530,8 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
> if (pkt_dev->flags & F_IPDST_RND) {
>
> do {
> - t = prandom_u32() %
> - (imx - imn) + imn;
> + t = prandom_u32_max(imx - imn) +
> + imn;
> s = htonl(t);
> } while (ipv4_is_loopback(s) ||
> ipv4_is_multicast(s) ||
> @@ -2579,9 +2578,9 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
> if (pkt_dev->min_pkt_size < pkt_dev->max_pkt_size) {
> __u32 t;
> if (pkt_dev->flags & F_TXSIZE_RND) {
> - t = prandom_u32() %
> - (pkt_dev->max_pkt_size - pkt_dev->min_pkt_size)
> - + pkt_dev->min_pkt_size;
> + t = prandom_u32_max(pkt_dev->max_pkt_size -
> + pkt_dev->min_pkt_size) +
> + pkt_dev->min_pkt_size;
> } else {
> t = pkt_dev->cur_pkt_size + 1;
> if (t > pkt_dev->max_pkt_size)
> @@ -2590,7 +2589,7 @@ static void mod_cur_headers(struct pktgen_dev *pkt_dev)
> pkt_dev->cur_pkt_size = t;
> } else if (pkt_dev->n_imix_entries > 0) {
> struct imix_pkt *entry;
> - __u32 t = prandom_u32() % IMIX_PRECISION;
> + __u32 t = prandom_u32_max(IMIX_PRECISION);
> __u8 entry_index = pkt_dev->imix_distribution[t];
>
> entry = &pkt_dev->imix_entries[entry_index];
> diff --git a/net/core/stream.c b/net/core/stream.c
> index ccc083cdef23..4780558ea314 100644
> --- a/net/core/stream.c
> +++ b/net/core/stream.c
> @@ -123,7 +123,7 @@ int sk_stream_wait_memory(struct sock *sk, long *timeo_p)
> DEFINE_WAIT_FUNC(wait, woken_wake_function);
>
> if (sk_stream_memory_free(sk))
> - current_timeo = vm_wait = (prandom_u32() % (HZ / 5)) + 2;
> + current_timeo = vm_wait = prandom_u32_max(HZ / 5) + 2;
>
> add_wait_queue(sk_sleep(sk), &wait);
>
> diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
> index e3ab0cb61624..9149e78beea5 100644
> --- a/net/ipv4/igmp.c
> +++ b/net/ipv4/igmp.c
> @@ -213,7 +213,7 @@ static void igmp_stop_timer(struct ip_mc_list *im)
> /* It must be called with locked im->lock */
> static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
> {
> - int tv = prandom_u32() % max_delay;
> + int tv = prandom_u32_max(max_delay);
>
> im->tm_running = 1;
> if (!mod_timer(&im->timer, jiffies+tv+2))
> @@ -222,7 +222,7 @@ static void igmp_start_timer(struct ip_mc_list *im, int max_delay)
>
> static void igmp_gq_start_timer(struct in_device *in_dev)
> {
> - int tv = prandom_u32() % in_dev->mr_maxdelay;
> + int tv = prandom_u32_max(in_dev->mr_maxdelay);
> unsigned long exp = jiffies + tv + 2;
>
> if (in_dev->mr_gq_running &&
> @@ -236,7 +236,7 @@ static void igmp_gq_start_timer(struct in_device *in_dev)
>
> static void igmp_ifc_start_timer(struct in_device *in_dev, int delay)
> {
> - int tv = prandom_u32() % delay;
> + int tv = prandom_u32_max(delay);
>
> if (!mod_timer(&in_dev->mr_ifc_timer, jiffies+tv+2))
> in_dev_hold(in_dev);
> diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
> index eb31c7158b39..0c3eab1347cd 100644
> --- a/net/ipv4/inet_connection_sock.c
> +++ b/net/ipv4/inet_connection_sock.c
> @@ -223,7 +223,7 @@ inet_csk_find_open_port(struct sock *sk, struct inet_bind_bucket **tb_ret, int *
> if (likely(remaining > 1))
> remaining &= ~1U;
>
> - offset = prandom_u32() % remaining;
> + offset = prandom_u32_max(remaining);
> /* __inet_hash_connect() favors ports having @low parity
> * We do the opposite to not pollute connect() users.
> */
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 10ce86bf228e..417834b7169d 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -104,7 +104,7 @@ static inline u32 cstamp_delta(unsigned long cstamp)
> static inline s32 rfc3315_s14_backoff_init(s32 irt)
> {
> /* multiply 'initial retransmission time' by 0.9 .. 1.1 */
> - u64 tmp = (900000 + prandom_u32() % 200001) * (u64)irt;
> + u64 tmp = (900000 + prandom_u32_max(200001)) * (u64)irt;
> do_div(tmp, 1000000);
> return (s32)tmp;
> }
> @@ -112,11 +112,11 @@ static inline s32 rfc3315_s14_backoff_init(s32 irt)
> static inline s32 rfc3315_s14_backoff_update(s32 rt, s32 mrt)
> {
> /* multiply 'retransmission timeout' by 1.9 .. 2.1 */
> - u64 tmp = (1900000 + prandom_u32() % 200001) * (u64)rt;
> + u64 tmp = (1900000 + prandom_u32_max(200001)) * (u64)rt;
> do_div(tmp, 1000000);
> if ((s32)tmp > mrt) {
> /* multiply 'maximum retransmission time' by 0.9 .. 1.1 */
> - tmp = (900000 + prandom_u32() % 200001) * (u64)mrt;
> + tmp = (900000 + prandom_u32_max(200001)) * (u64)mrt;
> do_div(tmp, 1000000);
> }
> return (s32)tmp;
> @@ -3967,7 +3967,7 @@ static void addrconf_dad_kick(struct inet6_ifaddr *ifp)
> if (ifp->flags & IFA_F_OPTIMISTIC)
> rand_num = 0;
> else
> - rand_num = prandom_u32() % (idev->cnf.rtr_solicit_delay ? : 1);
> + rand_num = prandom_u32_max(idev->cnf.rtr_solicit_delay ?: 1);
>
> nonce = 0;
> if (idev->cnf.enhanced_dad ||
> diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c
> index 87c699d57b36..bf4f5edb3c3e 100644
> --- a/net/ipv6/mcast.c
> +++ b/net/ipv6/mcast.c
> @@ -1050,7 +1050,7 @@ bool ipv6_chk_mcast_addr(struct net_device *dev, const struct in6_addr *group,
> /* called with mc_lock */
> static void mld_gq_start_work(struct inet6_dev *idev)
> {
> - unsigned long tv = prandom_u32() % idev->mc_maxdelay;
> + unsigned long tv = prandom_u32_max(idev->mc_maxdelay);
>
> idev->mc_gq_running = 1;
> if (!mod_delayed_work(mld_wq, &idev->mc_gq_work, tv + 2))
> @@ -1068,7 +1068,7 @@ static void mld_gq_stop_work(struct inet6_dev *idev)
> /* called with mc_lock */
> static void mld_ifc_start_work(struct inet6_dev *idev, unsigned long delay)
> {
> - unsigned long tv = prandom_u32() % delay;
> + unsigned long tv = prandom_u32_max(delay);
>
> if (!mod_delayed_work(mld_wq, &idev->mc_ifc_work, tv + 2))
> in6_dev_hold(idev);
> @@ -1085,7 +1085,7 @@ static void mld_ifc_stop_work(struct inet6_dev *idev)
> /* called with mc_lock */
> static void mld_dad_start_work(struct inet6_dev *idev, unsigned long delay)
> {
> - unsigned long tv = prandom_u32() % delay;
> + unsigned long tv = prandom_u32_max(delay);
>
> if (!mod_delayed_work(mld_wq, &idev->mc_dad_work, tv + 2))
> in6_dev_hold(idev);
> @@ -1130,7 +1130,7 @@ static void igmp6_group_queried(struct ifmcaddr6 *ma, unsigned long resptime)
> }
>
> if (delay >= resptime)
> - delay = prandom_u32() % resptime;
> + delay = prandom_u32_max(resptime);
>
> if (!mod_delayed_work(mld_wq, &ma->mca_work, delay))
> refcount_inc(&ma->mca_refcnt);
> @@ -2574,7 +2574,7 @@ static void igmp6_join_group(struct ifmcaddr6 *ma)
>
> igmp6_send(&ma->mca_addr, ma->idev->dev, ICMPV6_MGM_REPORT);
>
> - delay = prandom_u32() % unsolicited_report_interval(ma->idev);
> + delay = prandom_u32_max(unsolicited_report_interval(ma->idev));
>
> if (cancel_delayed_work(&ma->mca_work)) {
> refcount_dec(&ma->mca_refcnt);
> diff --git a/net/netfilter/ipvs/ip_vs_twos.c b/net/netfilter/ipvs/ip_vs_twos.c
> index acb55d8393ef..f2579fc9c75b 100644
> --- a/net/netfilter/ipvs/ip_vs_twos.c
> +++ b/net/netfilter/ipvs/ip_vs_twos.c
> @@ -71,8 +71,8 @@ static struct ip_vs_dest *ip_vs_twos_schedule(struct ip_vs_service *svc,
> * from 0 to total_weight
> */
> total_weight += 1;
> - rweight1 = prandom_u32() % total_weight;
> - rweight2 = prandom_u32() % total_weight;
> + rweight1 = prandom_u32_max(total_weight);
> + rweight2 = prandom_u32_max(total_weight);
>
> /* Pick two weighted servers */
> list_for_each_entry_rcu(dest, &svc->destinations, n_list) {
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 5cbe07116e04..331f80e12779 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -1350,7 +1350,7 @@ static bool fanout_flow_is_huge(struct packet_sock *po, struct sk_buff *skb)
> if (READ_ONCE(history[i]) == rxhash)
> count++;
>
> - victim = prandom_u32() % ROLLOVER_HLEN;
> + victim = prandom_u32_max(ROLLOVER_HLEN);
>
> /* Avoid dirtying the cache line if possible */
> if (READ_ONCE(history[victim]) != rxhash)
> diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
> index ac29d1065232..1accaedef54f 100644
> --- a/net/sched/act_gact.c
> +++ b/net/sched/act_gact.c
> @@ -26,7 +26,7 @@ static struct tc_action_ops act_gact_ops;
> static int gact_net_rand(struct tcf_gact *gact)
> {
> smp_rmb(); /* coupled with smp_wmb() in tcf_gact_init() */
> - if (prandom_u32() % gact->tcfg_pval)
> + if (prandom_u32_max(gact->tcfg_pval))
> return gact->tcf_action;
> return gact->tcfg_paction;
> }
> diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
> index 2f7f5e44d28c..55c9f961fb0f 100644
> --- a/net/sched/act_sample.c
> +++ b/net/sched/act_sample.c
> @@ -169,7 +169,7 @@ static int tcf_sample_act(struct sk_buff *skb, const struct tc_action *a,
> psample_group = rcu_dereference_bh(s->psample_group);
>
> /* randomly sample packets according to rate */
> - if (psample_group && (prandom_u32() % s->rate == 0)) {
> + if (psample_group && (prandom_u32_max(s->rate) == 0)) {
> if (!skb_at_tc_ingress(skb)) {
> md.in_ifindex = skb->skb_iif;
> md.out_ifindex = skb->dev->ifindex;
> diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
> index 5449ed114e40..3ca320f1a031 100644
> --- a/net/sched/sch_netem.c
> +++ b/net/sched/sch_netem.c
> @@ -513,8 +513,8 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
> goto finish_segs;
> }
>
> - skb->data[prandom_u32() % skb_headlen(skb)] ^=
> - 1<<(prandom_u32() % 8);
> + skb->data[prandom_u32_max(skb_headlen(skb))] ^=
> + 1<<prandom_u32_max(8);
> }
>
> if (unlikely(sch->q.qlen >= sch->limit)) {
> diff --git a/net/sctp/socket.c b/net/sctp/socket.c
> index 171f1a35d205..1e354ba44960 100644
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -8319,7 +8319,7 @@ static int sctp_get_port_local(struct sock *sk, union sctp_addr *addr)
>
> inet_get_local_port_range(net, &low, &high);
> remaining = (high - low) + 1;
> - rover = prandom_u32() % remaining + low;
> + rover = prandom_u32_max(remaining) + low;
>
> do {
> rover++;
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index f1c3b8eb4b3d..e902b01ea3cb 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -3010,7 +3010,7 @@ static int tipc_sk_insert(struct tipc_sock *tsk)
> struct net *net = sock_net(sk);
> struct tipc_net *tn = net_generic(net, tipc_net_id);
> u32 remaining = (TIPC_MAX_PORT - TIPC_MIN_PORT) + 1;
> - u32 portid = prandom_u32() % remaining + TIPC_MIN_PORT;
> + u32 portid = prandom_u32_max(remaining) + TIPC_MIN_PORT;
>
> while (remaining--) {
> portid++;
> diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
> index 91c32a3b6924..b213c89cfb8a 100644
> --- a/net/xfrm/xfrm_state.c
> +++ b/net/xfrm/xfrm_state.c
> @@ -2072,7 +2072,7 @@ int xfrm_alloc_spi(struct xfrm_state *x, u32 low, u32 high)
> } else {
> u32 spi = 0;
> for (h = 0; h < high-low+1; h++) {
> - spi = low + prandom_u32()%(high-low+1);
> + spi = low + prandom_u32_max(high - low + 1);
> x0 = xfrm_state_lookup(net, mark, &x->id.daddr, htonl(spi), x->id.proto, x->props.family);
> if (x0 == NULL) {
> newspi = htonl(spi);
> --
> 2.37.3
>