* + zram-switch-to-unsigned-long-indexing.patch added to mm-new branch
@ 2026-08-06 4:16 Andrew Morton
0 siblings, 0 replies; only message in thread
From: Andrew Morton @ 2026-08-06 4:16 UTC (permalink / raw)
To: mm-commits, xialonglong2025, minchan, akpm, senozhatsky, akpm
The patch titled
Subject: zram: switch to unsigned long indexing
has been added to the -mm mm-new branch. Its filename is
zram-switch-to-unsigned-long-indexing.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/zram-switch-to-unsigned-long-indexing.patch
This patch will later appear in the mm-new branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews. Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.
The mm-new branch of mm.git is not included in linux-next
If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days
------------------------------------------------------
From: Sergey Senozhatsky <senozhatsky@chromium.org>
Subject: zram: switch to unsigned long indexing
Date: Thu, 6 Aug 2026 12:16:32 +0900
zram has always used "unsigned int" for (page) index calculations, which
unnecessarily limited max zram disksize.
Switch to "unsigned long" and permit much larger zram devices.
Link: https://lore.kernel.org/20260806031640.536615-1-senozhatsky@chromium.org
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Co-developed-by: Longlong Xia <xialonglong2025@163.com>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/block/zram/zram_drv.c | 137 +++++++++++++++++---------------
1 file changed, 77 insertions(+), 60 deletions(-)
--- a/drivers/block/zram/zram_drv.c~zram-switch-to-unsigned-long-indexing
+++ a/drivers/block/zram/zram_drv.c
@@ -56,7 +56,7 @@ static size_t huge_class_size;
static const struct block_device_operations zram_devops;
-static void slot_free(struct zram *zram, u32 index);
+static void slot_free(struct zram *zram, unsigned long index);
/*
* entry locking rules:
@@ -70,7 +70,7 @@ static void slot_free(struct zram *zram,
* 4) Use TRY lock variant when in atomic context
* - must check return value and handle locking failers
*/
-static __must_check bool slot_trylock(struct zram *zram, u32 index)
+static __must_check bool slot_trylock(struct zram *zram, unsigned long index)
{
unsigned long *lock = &zram->table[index].__lock;
@@ -83,7 +83,7 @@ static __must_check bool slot_trylock(st
return false;
}
-static void slot_lock(struct zram *zram, u32 index)
+static void slot_lock(struct zram *zram, unsigned long index)
{
unsigned long *lock = &zram->table[index].__lock;
@@ -92,7 +92,7 @@ static void slot_lock(struct zram *zram,
lock_acquired(&zram->table_lock_map, _RET_IP_);
}
-static void slot_unlock(struct zram *zram, u32 index)
+static void slot_unlock(struct zram *zram, unsigned long index)
{
unsigned long *lock = &zram->table[index].__lock;
@@ -110,55 +110,56 @@ static inline struct zram *dev_to_zram(s
return (struct zram *)dev_to_disk(dev)->private_data;
}
-static unsigned long get_slot_handle(struct zram *zram, u32 index)
+static unsigned long get_slot_handle(struct zram *zram, unsigned long index)
{
return zram->table[index].handle;
}
-static void set_slot_handle(struct zram *zram, u32 index, unsigned long handle)
+static void set_slot_handle(struct zram *zram, unsigned long index,
+ unsigned long handle)
{
zram->table[index].handle = handle;
}
-static bool test_slot_flag(struct zram *zram, u32 index,
+static bool test_slot_flag(struct zram *zram, unsigned long index,
enum zram_pageflags flag)
{
return zram->table[index].attr.flags & BIT(flag);
}
-static void set_slot_flag(struct zram *zram, u32 index,
+static void set_slot_flag(struct zram *zram, unsigned long index,
enum zram_pageflags flag)
{
zram->table[index].attr.flags |= BIT(flag);
}
-static void clear_slot_flag(struct zram *zram, u32 index,
+static void clear_slot_flag(struct zram *zram, unsigned long index,
enum zram_pageflags flag)
{
zram->table[index].attr.flags &= ~BIT(flag);
}
-static size_t get_slot_size(struct zram *zram, u32 index)
+static size_t get_slot_size(struct zram *zram, unsigned long index)
{
return zram->table[index].attr.flags & (BIT(ZRAM_FLAG_SHIFT) - 1);
}
-static void set_slot_size(struct zram *zram, u32 index, size_t size)
+static void set_slot_size(struct zram *zram, unsigned long index, size_t size)
{
unsigned long flags = zram->table[index].attr.flags >> ZRAM_FLAG_SHIFT;
zram->table[index].attr.flags = (flags << ZRAM_FLAG_SHIFT) | size;
}
-static inline bool slot_allocated(struct zram *zram, u32 index)
+static inline bool slot_allocated(struct zram *zram, unsigned long index)
{
return get_slot_size(zram, index) ||
test_slot_flag(zram, index, ZRAM_SAME) ||
test_slot_flag(zram, index, ZRAM_WB);
}
-static inline void set_slot_comp_priority(struct zram *zram, u32 index,
- u32 prio)
+static inline void set_slot_comp_priority(struct zram *zram,
+ unsigned long index, u32 prio)
{
prio &= ZRAM_COMP_PRIORITY_MASK;
/*
@@ -170,14 +171,14 @@ static inline void set_slot_comp_priorit
zram->table[index].attr.flags |= (prio << ZRAM_COMP_PRIORITY_BIT1);
}
-static inline u32 get_slot_comp_priority(struct zram *zram, u32 index)
+static inline u32 get_slot_comp_priority(struct zram *zram, unsigned long index)
{
u32 prio = zram->table[index].attr.flags >> ZRAM_COMP_PRIORITY_BIT1;
return prio & ZRAM_COMP_PRIORITY_MASK;
}
-static void mark_slot_accessed(struct zram *zram, u32 index)
+static void mark_slot_accessed(struct zram *zram, unsigned long index)
{
clear_slot_flag(zram, index, ZRAM_IDLE);
clear_slot_flag(zram, index, ZRAM_PP_SLOT);
@@ -284,7 +285,7 @@ static void release_pp_ctl(struct zram *
}
static bool place_pp_slot(struct zram *zram, struct zram_pp_ctl *ctl,
- u32 index)
+ unsigned long index)
{
struct zram_pp_slot *pps;
u32 bid;
@@ -418,7 +419,7 @@ static void mark_idle(struct zram *zram,
{
int is_idle = 1;
unsigned long nr_pages = zram->disksize >> PAGE_SHIFT;
- int index;
+ unsigned long index;
for (index = 0; index < nr_pages; index++) {
/*
@@ -485,8 +486,9 @@ static ssize_t idle_store(struct device
#define INVALID_BDEV_BLOCK (~0UL)
static int read_from_zspool_raw(struct zram *zram, struct page *page,
- u32 index);
-static int read_from_zspool(struct zram *zram, struct page *page, u32 index);
+ unsigned long index);
+static int read_from_zspool(struct zram *zram, struct page *page,
+ unsigned long index);
struct zram_wb_ctl {
/* idle list is accessed only by the writeback task, no concurency */
@@ -522,7 +524,7 @@ struct zram_rb_req {
/* error status (sync read) */
int error;
};
- u32 index;
+ unsigned long index;
};
#define FOUR_K(x) ((x) * (1 << (PAGE_SHIFT - 12)))
@@ -910,7 +912,7 @@ static void zram_account_writeback_submi
static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
{
- u32 index = req->pps->index;
+ unsigned long index = req->pps->index;
int err;
err = blk_status_to_errno(req->bio.bi_status);
@@ -1032,7 +1034,7 @@ static int zram_writeback_slots(struct z
struct zram_wb_req *req = NULL;
struct zram_pp_slot *pps;
int ret = 0, err = 0;
- u32 index = 0;
+ unsigned long index = 0;
while ((pps = select_pp_slot(ctl))) {
if (zram->wb_limit_enable && !zram->bd_wb_limit) {
@@ -1198,7 +1200,7 @@ static void scan_slots_for_writeback(str
unsigned long lo, unsigned long hi,
struct zram_pp_ctl *ctl)
{
- u32 index = lo;
+ unsigned long index = lo;
while (index < hi) {
bool ok = true;
@@ -1235,7 +1237,7 @@ static ssize_t writeback_store(struct de
const char *buf, size_t len)
{
struct zram *zram = dev_to_zram(dev);
- u64 nr_pages;
+ unsigned long nr_pages;
unsigned long lo = 0, hi;
struct zram_pp_ctl *pp_ctl = NULL;
struct zram_wb_ctl *wb_ctl = NULL;
@@ -1336,7 +1338,8 @@ out:
return ret;
}
-static int decompress_bdev_page(struct zram *zram, struct page *page, u32 index)
+static int decompress_bdev_page(struct zram *zram, struct page *page,
+ unsigned long index)
{
struct zcomp_strm *zstrm;
unsigned int size;
@@ -1378,7 +1381,7 @@ static void zram_deferred_decompress(str
struct zram_rb_req *req = container_of(w, struct zram_rb_req, work);
struct page *page = bio_first_page_all(req->bio);
struct zram *zram = req->zram;
- u32 index = req->index;
+ unsigned long index = req->index;
int ret;
ret = decompress_bdev_page(zram, page, index);
@@ -1429,7 +1432,7 @@ static void zram_async_read_endio(struct
}
static int read_from_bdev_async(struct zram *zram, struct page *page,
- u32 index, unsigned long blk_idx,
+ unsigned long index, unsigned long blk_idx,
struct bio *parent)
{
struct zram_rb_req *req;
@@ -1479,8 +1482,8 @@ static void zram_sync_read(struct work_s
* chained IO with parent IO in same context, it's a deadlock. To avoid that,
* use a worker thread context.
*/
-static int read_from_bdev_sync(struct zram *zram, struct page *page, u32 index,
- unsigned long blk_idx)
+static int read_from_bdev_sync(struct zram *zram, struct page *page,
+ unsigned long index, unsigned long blk_idx)
{
struct zram_rb_req req;
@@ -1499,8 +1502,9 @@ static int read_from_bdev_sync(struct zr
return decompress_bdev_page(zram, page, index);
}
-static int read_from_bdev(struct zram *zram, struct page *page, u32 index,
- unsigned long blk_idx, struct bio *parent)
+static int read_from_bdev(struct zram *zram, struct page *page,
+ unsigned long index, unsigned long blk_idx,
+ struct bio *parent)
{
atomic64_inc(&zram->stats.bd_reads);
if (!parent) {
@@ -1512,8 +1516,9 @@ static int read_from_bdev(struct zram *z
}
#else
static inline void reset_bdev(struct zram *zram) {};
-static int read_from_bdev(struct zram *zram, struct page *page, u32 index,
- unsigned long blk_idx, struct bio *parent)
+static int read_from_bdev(struct zram *zram, struct page *page,
+ unsigned long index, unsigned long blk_idx,
+ struct bio *parent)
{
return -EIO;
}
@@ -1541,7 +1546,8 @@ static ssize_t read_block_state(struct f
size_t count, loff_t *ppos)
{
char *kbuf;
- ssize_t index, written = 0;
+ unsigned long index;
+ ssize_t written = 0;
struct zram *zram = file->private_data;
unsigned long nr_pages;
@@ -1565,7 +1571,7 @@ static ssize_t read_block_state(struct f
goto next;
copied = snprintf(kbuf + written, count,
- "%12zd %12u.%06d %c%c%c%c%c%c\n",
+ "%12lu %12u.%06d %c%c%c%c%c%c\n",
index, zram->table[index].attr.ac_time, 0,
test_slot_flag(zram, index, ZRAM_SAME) ? 's' : '.',
test_slot_flag(zram, index, ZRAM_WB) ? 'w' : '.',
@@ -1972,8 +1978,8 @@ static ssize_t debug_stat_show(struct de
static void zram_meta_free(struct zram *zram, u64 disksize)
{
- size_t num_pages = disksize >> PAGE_SHIFT;
- size_t index;
+ unsigned long num_pages = disksize >> PAGE_SHIFT;
+ unsigned long index;
if (!zram->table)
return;
@@ -1990,7 +1996,7 @@ static void zram_meta_free(struct zram *
static bool zram_meta_alloc(struct zram *zram, u64 disksize)
{
- size_t num_pages;
+ unsigned long num_pages;
num_pages = disksize >> PAGE_SHIFT;
zram->table = vzalloc(array_size(num_pages, sizeof(*zram->table)));
@@ -2013,7 +2019,7 @@ static bool zram_meta_alloc(struct zram
return true;
}
-static void slot_free(struct zram *zram, u32 index)
+static void slot_free(struct zram *zram, unsigned long index)
{
unsigned long handle;
@@ -2067,7 +2073,7 @@ out:
}
static int read_same_filled_page(struct zram *zram, struct page *page,
- u32 index)
+ unsigned long index)
{
void *mem;
@@ -2078,7 +2084,7 @@ static int read_same_filled_page(struct
}
static int read_incompressible_page(struct zram *zram, struct page *page,
- u32 index)
+ unsigned long index)
{
unsigned long handle;
void *src, *dst;
@@ -2093,7 +2099,8 @@ static int read_incompressible_page(stru
return 0;
}
-static int read_compressed_page(struct zram *zram, struct page *page, u32 index)
+static int read_compressed_page(struct zram *zram, struct page *page,
+ unsigned long index)
{
struct zcomp_strm *zstrm;
unsigned long handle;
@@ -2118,7 +2125,8 @@ static int read_compressed_page(struct z
}
#if defined CONFIG_ZRAM_WRITEBACK
-static int read_from_zspool_raw(struct zram *zram, struct page *page, u32 index)
+static int read_from_zspool_raw(struct zram *zram, struct page *page,
+ unsigned long index)
{
struct zcomp_strm *zstrm;
unsigned long handle;
@@ -2150,7 +2158,8 @@ static int read_from_zspool_raw(struct z
* Reads (decompresses if needed) a page from zspool (zsmalloc).
* Corresponding ZRAM slot should be locked.
*/
-static int read_from_zspool(struct zram *zram, struct page *page, u32 index)
+static int read_from_zspool(struct zram *zram, struct page *page,
+ unsigned long index)
{
if (test_slot_flag(zram, index, ZRAM_SAME) ||
!get_slot_handle(zram, index))
@@ -2162,8 +2171,8 @@ static int read_from_zspool(struct zram
return read_incompressible_page(zram, page, index);
}
-static int zram_read_page(struct zram *zram, struct page *page, u32 index,
- struct bio *parent)
+static int zram_read_page(struct zram *zram, struct page *page,
+ unsigned long index, struct bio *parent)
{
int ret;
@@ -2185,7 +2194,7 @@ static int zram_read_page(struct zram *z
/* Should NEVER happen. Return bio error if it does. */
if (WARN_ON(ret < 0))
- pr_err("Decompression failed! err=%d, page=%u\n", ret, index);
+ pr_err("Decompression failed! err=%d, page=%lu\n", ret, index);
return ret;
}
@@ -2195,7 +2204,7 @@ static int zram_read_page(struct zram *z
* always expects a full page for the output.
*/
static int zram_bvec_read_partial(struct zram *zram, struct bio_vec *bvec,
- u32 index, int offset)
+ unsigned long index, int offset)
{
struct page *page = alloc_page(GFP_NOIO);
int ret;
@@ -2210,7 +2219,7 @@ static int zram_bvec_read_partial(struct
}
static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
- u32 index, int offset, struct bio *bio)
+ unsigned long index, int offset, struct bio *bio)
{
if (is_partial_io(bvec))
return zram_bvec_read_partial(zram, bvec, index, offset);
@@ -2218,7 +2227,7 @@ static int zram_bvec_read(struct zram *z
}
static int write_same_filled_page(struct zram *zram, unsigned long fill,
- u32 index)
+ unsigned long index)
{
slot_lock(zram, index);
slot_free(zram, index);
@@ -2233,7 +2242,7 @@ static int write_same_filled_page(struct
}
static int write_incompressible_page(struct zram *zram, struct page *page,
- u32 index)
+ unsigned long index)
{
unsigned long handle;
void *src;
@@ -2273,7 +2282,8 @@ static int write_incompressible_page(str
return 0;
}
-static int zram_write_page(struct zram *zram, struct page *page, u32 index)
+static int zram_write_page(struct zram *zram, struct page *page,
+ unsigned long index)
{
int ret = 0;
unsigned long handle;
@@ -2340,7 +2350,7 @@ static int zram_write_page(struct zram *
* This is a partial IO. Read the full page before writing the changes.
*/
static int zram_bvec_write_partial(struct zram *zram, struct bio_vec *bvec,
- u32 index, int offset)
+ unsigned long index, int offset)
{
struct page *page = alloc_page(GFP_NOIO);
int ret;
@@ -2358,7 +2368,7 @@ static int zram_bvec_write_partial(struc
}
static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
- u32 index, int offset)
+ unsigned long index, int offset)
{
if (is_partial_io(bvec))
return zram_bvec_write_partial(zram, bvec, index, offset);
@@ -2426,8 +2436,9 @@ next:
*
* Corresponding ZRAM slot should be locked.
*/
-static int recompress_slot(struct zram *zram, u32 index, struct page *page,
- u64 *num_recomp_pages, u32 threshold, u32 prio)
+static int recompress_slot(struct zram *zram, unsigned long index,
+ struct page *page, u64 *num_recomp_pages,
+ u32 threshold, u32 prio)
{
struct zcomp_strm *zstrm = NULL;
unsigned long handle_old;
@@ -2679,7 +2690,7 @@ out:
static void zram_bio_discard(struct zram *zram, struct bio *bio)
{
size_t n = bio->bi_iter.bi_size;
- u32 index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
+ unsigned long index = bio->bi_iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
u32 offset = (bio->bi_iter.bi_sector & (SECTORS_PER_PAGE - 1)) <<
SECTOR_SHIFT;
@@ -2720,7 +2731,7 @@ static void zram_bio_read(struct zram *z
struct bvec_iter iter = bio->bi_iter;
do {
- u32 index = iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
+ unsigned long index = iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
u32 offset = (iter.bi_sector & (SECTORS_PER_PAGE - 1)) <<
SECTOR_SHIFT;
struct bio_vec bv = bio_iter_iovec(bio, iter);
@@ -2751,7 +2762,7 @@ static void zram_bio_write(struct zram *
struct bvec_iter iter = bio->bi_iter;
do {
- u32 index = iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
+ unsigned long index = iter.bi_sector >> SECTORS_PER_PAGE_SHIFT;
u32 offset = (iter.bi_sector & (SECTORS_PER_PAGE - 1)) <<
SECTOR_SHIFT;
struct bio_vec bv = bio_iter_iovec(bio, iter);
@@ -2865,6 +2876,7 @@ static void zram_reset_device(struct zra
static ssize_t disksize_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t len)
{
+ unsigned long num_pages;
u64 disksize;
struct zcomp *comp;
struct zram *zram = dev_to_zram(dev);
@@ -2882,6 +2894,11 @@ static ssize_t disksize_store(struct dev
}
disksize = PAGE_ALIGN(disksize);
+ num_pages = disksize >> PAGE_SHIFT;
+ /* Slots are addressed by an unsigned long index */
+ if (!num_pages || ((u64)num_pages << PAGE_SHIFT) != disksize)
+ return -EINVAL;
+
if (!zram_meta_alloc(zram, disksize))
return -ENOMEM;
_
Patches currently in -mm which might be from senozhatsky@chromium.org are
documentation-zram-remove-sections-numbering.patch
zram-set-default-primary-compressor-in-zram_destroy_comps.patch
zram-validate-deflate-params.patch
documentation-zram-correct-algo-parameters-configuration-documentation.patch
zram-switch-to-unsigned-long-indexing.patch
^ permalink raw reply [flat|nested] only message in thread
only message in thread, other threads:[~2026-08-06 4:16 UTC | newest]
Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-08-06 4:16 + zram-switch-to-unsigned-long-indexing.patch added to mm-new branch Andrew Morton
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.