path: root/drivers/md/dm-integrity.c
diff options
authorMark Rutland <mark.rutland@arm.com>2017-10-23 14:07:11 -0700
committerIngo Molnar <mingo@kernel.org>2017-10-25 11:00:55 +0200
commitd3e632f07b6e637d3643081873867ecb6433b2ce (patch)
tree8272116f295ba66e85647d1ba2fce679e59b9326 /drivers/md/dm-integrity.c
parentlocking/qrwlock: Prevent slowpath writers getting held up by fastpath (diff)
locking/atomics, dm-integrity: Convert ACCESS_ONCE() to READ_ONCE()/WRITE_ONCE()
For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't currently harmful. However, for some features it is necessary to instrument reads and writes separately, which is not possible with ACCESS_ONCE(). This distinction is critical to correct operation. It's possible to transform the bulk of kernel code using the Coccinelle script below. However, this doesn't pick up some uses, including those in dm-integrity.c. As a preparatory step, this patch converts the driver to use {READ,WRITE}_ONCE() consistently. At the same time, this patch adds the missing include of <linux/compiler.h> necessary for the {READ,WRITE}_ONCE() definitions. ---- virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-1-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/md/dm-integrity.c')
1 files changed, 8 insertions, 7 deletions
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 096fe9b66c50..8c5756e1df94 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -6,6 +6,7 @@
* This file is released under the GPL.
+#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/device-mapper.h>
#include <linux/dm-io.h>
@@ -80,13 +81,13 @@ struct journal_entry {
#define journal_entry_tag(ic, je) ((__u8 *)&(je)->last_bytes[(ic)->sectors_per_block])
#if BITS_PER_LONG == 64
-#define journal_entry_set_sector(je, x) do { smp_wmb(); ACCESS_ONCE((je)->u.sector) = cpu_to_le64(x); } while (0)
+#define journal_entry_set_sector(je, x) do { smp_wmb(); WRITE_ONCE((je)->u.sector, cpu_to_le64(x)); } while (0)
#define journal_entry_get_sector(je) le64_to_cpu((je)->u.sector)
#elif defined(CONFIG_LBDAF)
-#define journal_entry_set_sector(je, x) do { (je)->u.s.sector_lo = cpu_to_le32(x); smp_wmb(); ACCESS_ONCE((je)->u.s.sector_hi) = cpu_to_le32((x) >> 32); } while (0)
+#define journal_entry_set_sector(je, x) do { (je)->u.s.sector_lo = cpu_to_le32(x); smp_wmb(); WRITE_ONCE((je)->u.s.sector_hi, cpu_to_le32((x) >> 32)); } while (0)
#define journal_entry_get_sector(je) le64_to_cpu((je)->u.sector)
-#define journal_entry_set_sector(je, x) do { (je)->u.s.sector_lo = cpu_to_le32(x); smp_wmb(); ACCESS_ONCE((je)->u.s.sector_hi) = cpu_to_le32(0); } while (0)
+#define journal_entry_set_sector(je, x) do { (je)->u.s.sector_lo = cpu_to_le32(x); smp_wmb(); WRITE_ONCE((je)->u.s.sector_hi, cpu_to_le32(0)); } while (0)
#define journal_entry_get_sector(je) le32_to_cpu((je)->u.s.sector_lo)
#define journal_entry_is_unused(je) ((je)->u.s.sector_hi == cpu_to_le32(-1))
@@ -320,7 +321,7 @@ static void dm_integrity_io_error(struct dm_integrity_c *ic, const char *msg, in
static int dm_integrity_failed(struct dm_integrity_c *ic)
- return ACCESS_ONCE(ic->failed);
+ return READ_ONCE(ic->failed);
static commit_id_t dm_integrity_commit_id(struct dm_integrity_c *ic, unsigned i,
@@ -1545,7 +1546,7 @@ retry_kmap:
if (unlikely(waitqueue_active(&ic->copy_to_journal_wait)))
- if (ACCESS_ONCE(ic->free_sectors) <= ic->free_sectors_threshold) {
+ if (READ_ONCE(ic->free_sectors) <= ic->free_sectors_threshold) {
queue_work(ic->commit_wq, &ic->commit_work);
} else {
@@ -1798,7 +1799,7 @@ static void integrity_commit(struct work_struct *w)
ic->n_committed_sections += commit_sections;
- if (ACCESS_ONCE(ic->free_sectors) <= ic->free_sectors_threshold)
+ if (READ_ONCE(ic->free_sectors) <= ic->free_sectors_threshold)
queue_work(ic->writer_wq, &ic->writer_work);
@@ -1980,7 +1981,7 @@ static void integrity_writer(struct work_struct *w)
unsigned prev_free_sectors;
/* the following test is not needed, but it tests the replay code */
- if (ACCESS_ONCE(ic->suspending))
+ if (READ_ONCE(ic->suspending))