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Donenfeld" To: linux-kernel@vger.kernel.org, patches@lists.linux.dev Subject: [PATCH v6 4/7] treewide: use get_random_{u8,u16}() when possible, part 2 Date: Mon, 10 Oct 2022 17:06:10 -0600 Message-Id: <20221010230613.1076905-5-Jason@zx2c4.com> In-Reply-To: <20221010230613.1076905-1-Jason@zx2c4.com> References: <20221010230613.1076905-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Tue, 11 Oct 2022 11:42:14 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-wireless@vger.kernel.org, "Jason A. Donenfeld" , x86@kernel.org, Vignesh Raghavendra , linux-doc@vger.kernel.org, Peter Zijlstra , Catalin Marinas , Dave Hansen , kernel-janitors@vger.kernel.org, KP Singh , dri-devel@lists.freedesktop.org, linux-mm@kvack.org, Eric Dumazet , netdev@vger.kernel.org, linux-mtd@lists.infradead.org, kasan-dev@googlegroups.com, "H . Peter Anvin" , Andreas Noever , WANG Xuerui , Will Deacon , Christoph Hellwig , linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, Mauro Carvalho Chehab , Herbert Xu , Daniel Borkmann , Jonathan Corbet , linux-rdma@vger.kernel.org, Helge Deller , Huacai Chen , Hugh Dickins , Russell King , Jozsef Kadlecsik , Jason Gunthorpe , Dave Airlie , Ulf Hansson , Paolo Abeni , "James E . J . Bottomley" , Pablo Neira Ayuso , linux-media@vger.kernel.org, Marco Elver , Kees Cook , Yury Norov , Heiko Carstens , linux-um@lists.infradead.org, linux-block@vger.kernel.org, Richard Weinberger , Borislav Petkov , linux-nvme@lists.infradead.org, loongarch@lists.linux.dev, Jakub Kicinski , Thomas Gleixner , Andy Shevchenko , Johannes Berg , linux-arm-kernel@lists.infradead.org, Jens Axboe , linux-mmc@vger.kernel.org, Thomas Bogendoerfer , Theodore Ts'o , linux-parisc@vger.kernel.org, Greg Kroah-Hartman , linux-usb@vger.kernel.org, Florian Westphal , linux-mips@vger.kernel.org, =?UTF-8?q?Christoph=20B=C3=B6hmwalder?= , linux-crypto@vger.kernel.org, Jan Kara , Thomas Graf , linux-fsdevel@vger.kernel.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org, "David S . Miller" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Rather than truncate a 32-bit value to a 16-bit value or an 8-bit value, simply use the get_random_{u8,u16}() functions, which are faster than wasting the additional bytes from a 32-bit value. This was done by hand, identifying all of the places where one of the random integer functions was used in a non-32-bit context. Reviewed-by: Greg Kroah-Hartman Reviewed-by: Kees Cook Reviewed-by: Yury Norov Signed-off-by: Jason A. Donenfeld --- arch/s390/kernel/process.c | 2 +- drivers/mtd/nand/raw/nandsim.c | 2 +- lib/test_vmalloc.c | 2 +- net/rds/bind.c | 2 +- net/sched/sch_sfb.c | 2 +- 5 files changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c index 5ec78555dd2e..42af4b3aa02b 100644 --- a/arch/s390/kernel/process.c +++ b/arch/s390/kernel/process.c @@ -230,7 +230,7 @@ unsigned long arch_align_stack(unsigned long sp) static inline unsigned long brk_rnd(void) { - return (get_random_int() & BRK_RND_MASK) << PAGE_SHIFT; + return (get_random_u16() & BRK_RND_MASK) << PAGE_SHIFT; } unsigned long arch_randomize_brk(struct mm_struct *mm) diff --git a/drivers/mtd/nand/raw/nandsim.c b/drivers/mtd/nand/raw/nandsim.c index 50bcf745e816..d211939c8bdd 100644 --- a/drivers/mtd/nand/raw/nandsim.c +++ b/drivers/mtd/nand/raw/nandsim.c @@ -1402,7 +1402,7 @@ static int ns_do_read_error(struct nandsim *ns, int num) static void ns_do_bit_flips(struct nandsim *ns, int num) { - if (bitflips && prandom_u32() < (1 << 22)) { + if (bitflips && get_random_u16() < (1 << 6)) { int flips = 1; if (bitflips > 1) flips = prandom_u32_max(bitflips) + 1; diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c index a26bbbf20e62..cf7780572f5b 100644 --- a/lib/test_vmalloc.c +++ b/lib/test_vmalloc.c @@ -80,7 +80,7 @@ static int random_size_align_alloc_test(void) int i; for (i = 0; i < test_loop_count; i++) { - rnd = prandom_u32(); + rnd = get_random_u8(); /* * Maximum 1024 pages, if PAGE_SIZE is 4096. diff --git a/net/rds/bind.c b/net/rds/bind.c index 5b5fb4ca8d3e..97a29172a8ee 100644 --- a/net/rds/bind.c +++ b/net/rds/bind.c @@ -104,7 +104,7 @@ static int rds_add_bound(struct rds_sock *rs, const struct in6_addr *addr, return -EINVAL; last = rover; } else { - rover = max_t(u16, prandom_u32(), 2); + rover = max_t(u16, get_random_u16(), 2); last = rover - 1; } diff --git a/net/sched/sch_sfb.c b/net/sched/sch_sfb.c index e2389fa3cff8..0366a1a029a9 100644 --- a/net/sched/sch_sfb.c +++ b/net/sched/sch_sfb.c @@ -379,7 +379,7 @@ static int sfb_enqueue(struct sk_buff *skb, struct Qdisc *sch, goto enqueue; } - r = prandom_u32() & SFB_MAX_PROB; + r = get_random_u16() & SFB_MAX_PROB; if (unlikely(r < p_min)) { if (unlikely(p_min > SFB_MAX_PROB / 2)) { -- 2.37.3