lkml.org 
[lkml]   [2021]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 03/23] io_uring: remove dependency on ring->sq/cq_entries
Date
We have numbers of {sq,cq} entries cached in ctx, don't look up them in
user-shared rings as 1) it may fetch additional cacheline 2) user may
change it and so it's always error prone.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io_uring.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 31eca208f675..15dc5dad1f7d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1352,7 +1352,7 @@ static inline bool io_sqring_full(struct io_ring_ctx *ctx)
{
struct io_rings *r = ctx->rings;

- return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == r->sq_ring_entries;
+ return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries;
}

static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
@@ -1370,7 +1370,7 @@ static inline struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
- if (__io_cqring_events(ctx) == rings->cq_ring_entries)
+ if (__io_cqring_events(ctx) == ctx->cq_entries)
return NULL;

tail = ctx->cached_cq_tail++;
@@ -1423,11 +1423,10 @@ static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx)
/* Returns true if there are no backlogged entries after the flush */
static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
{
- struct io_rings *rings = ctx->rings;
unsigned long flags;
bool all_flushed, posted;

- if (!force && __io_cqring_events(ctx) == rings->cq_ring_entries)
+ if (!force && __io_cqring_events(ctx) == ctx->cq_entries)
return false;

posted = false;
--
2.31.1
\
 
 \ /
  Last update: 2021-05-19 16:14    [W:0.108 / U:0.996 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site