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RDMA/ucma: Change backlog into an atomic

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There is no reason to grab the file->mut just to do this inc/dec work. Use
an atomic.

Link: https://lore.kernel.org/r/20200818120526.702120-12-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2020-08-18 15:05:23 +03:00
parent 38e03d0926
commit 26c15dec49
1 changed files with 8 additions and 7 deletions
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15
drivers/infiniband/core/ucma.c
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@ -88,7 +88,7 @@ struct ucma_context {
struct completion comp;
refcount_t ref;
int events_reported;
int backlog;
atomic_t backlog;
struct ucma_file *file;
struct rdma_cm_id *cm_id;
@ -348,12 +348,11 @@ static int ucma_event_handler(struct rdma_cm_id *cm_id,
uevent->resp.ece.attr_mod = event->ece.attr_mod;
if (event->event == RDMA_CM_EVENT_CONNECT_REQUEST) {
if (!ctx->backlog) {
if (!atomic_add_unless(&ctx->backlog, -1, 0)) {
ret = -ENOMEM;
kfree(uevent);
goto out;
}
ctx->backlog--;
} else if (!ctx->uid || ctx->cm_id != cm_id) {
/*
* We ignore events for new connections until userspace has set
@ -432,7 +431,7 @@ static ssize_t ucma_get_event(struct ucma_file *file, const char __user *inbuf,
}
if (ctx) {
uevent->ctx->backlog++;
atomic_inc(&uevent->ctx->backlog);
uevent->cm_id->context = ctx;
ucma_finish_ctx(ctx);
}
@ -1136,10 +1135,12 @@ static ssize_t ucma_listen(struct ucma_file *file, const char __user *inbuf,
if (IS_ERR(ctx))
return PTR_ERR(ctx);
ctx->backlog = cmd.backlog > 0 && cmd.backlog < max_backlog ?
cmd.backlog : max_backlog;
if (cmd.backlog <= 0 || cmd.backlog > max_backlog)
cmd.backlog = max_backlog;
atomic_set(&ctx->backlog, cmd.backlog);
mutex_lock(&ctx->mutex);
ret = rdma_listen(ctx->cm_id, ctx->backlog);
ret = rdma_listen(ctx->cm_id, cmd.backlog);
mutex_unlock(&ctx->mutex);
ucma_put_ctx(ctx);
return ret;