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iomap: protect read_bytes_pending with the state_lock

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Perform one atomic operation (acquiring the spinlock) instead of two
(spinlock & atomic_sub) per read completion.

Link: https://lkml.kernel.org/r/20231004165317.1061855-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2023-10-04 17:53:02 +01:00 committed by Andrew Morton
parent 279d5fc322
commit f45b494e2a
1 changed files with 25 additions and 12 deletions
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37
fs/iomap/buffered-io.c
View File

@ -29,9 +29,9 @@ typedef int (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length);
* and I/O completions.
*/
struct iomap_folio_state {
atomic_t read_bytes_pending;
atomic_t write_bytes_pending;
spinlock_t state_lock;
unsigned int read_bytes_pending;
atomic_t write_bytes_pending;
/*
* Each block has two bits in this bitmap:
@ -183,7 +183,7 @@ static void ifs_free(struct folio *folio)
if (!ifs)
return;
WARN_ON_ONCE(atomic_read(&ifs->read_bytes_pending));
WARN_ON_ONCE(ifs->read_bytes_pending != 0);
WARN_ON_ONCE(atomic_read(&ifs->write_bytes_pending));
WARN_ON_ONCE(ifs_is_fully_uptodate(folio, ifs) !=
folio_test_uptodate(folio));
@ -250,19 +250,29 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio,
*lenp = plen;
}
static void iomap_finish_folio_read(struct folio *folio, size_t offset,
static void iomap_finish_folio_read(struct folio *folio, size_t off,
size_t len, int error)
{
struct iomap_folio_state *ifs = folio->private;
bool uptodate = !error;
bool finished = true;
if (unlikely(error)) {
folio_clear_uptodate(folio);
folio_set_error(folio);
} else {
iomap_set_range_uptodate(folio, offset, len);
if (ifs) {
unsigned long flags;
spin_lock_irqsave(&ifs->state_lock, flags);
if (!error)
uptodate = ifs_set_range_uptodate(folio, ifs, off, len);
ifs->read_bytes_pending -= len;
finished = !ifs->read_bytes_pending;
spin_unlock_irqrestore(&ifs->state_lock, flags);
}
if (!ifs || atomic_sub_and_test(len, &ifs->read_bytes_pending))
if (error)
folio_set_error(folio);
if (uptodate)
folio_mark_uptodate(folio);
if (finished)
folio_unlock(folio);
}
@ -360,8 +370,11 @@ static loff_t iomap_readpage_iter(const struct iomap_iter *iter,
}
ctx->cur_folio_in_bio = true;
if (ifs)
atomic_add(plen, &ifs->read_bytes_pending);
if (ifs) {
spin_lock_irq(&ifs->state_lock);
ifs->read_bytes_pending += plen;
spin_unlock_irq(&ifs->state_lock);
}
sector = iomap_sector(iomap, pos);
if (!ctx->bio ||