From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, Eran Ben Elisha <eranbe@nvidia.com>,
Moshe Shemesh <moshe@nvidia.com>,
Saeed Mahameed <saeedm@nvidia.com>,
Timo Rothenpieler <timo@rothenpieler.org>
Subject: [PATCH 5.4 10/17] net/mlx5: Add retry mechanism to the command entry index allocation
Date: Fri, 20 Nov 2020 12:03:37 +0100 [thread overview]
Message-ID: <20201120104541.571471236@linuxfoundation.org> (raw)
In-Reply-To: <20201120104541.058449969@linuxfoundation.org>
From: Eran Ben Elisha <eranbe@nvidia.com>
commit 410bd754cd73c4a2ac3856d9a03d7b08f9c906bf upstream.
It is possible that new command entry index allocation will temporarily
fail. The new command holds the semaphore, so it means that a free entry
should be ready soon. Add one second retry mechanism before returning an
error.
Patch "net/mlx5: Avoid possible free of command entry while timeout comp
handler" increase the possibility to bump into this temporarily failure
as it delays the entry index release for non-callback commands.
Fixes: e126ba97dba9 ("mlx5: Add driver for Mellanox Connect-IB adapters")
Signed-off-by: Eran Ben Elisha <eranbe@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Cc: Timo Rothenpieler <timo@rothenpieler.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
--- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c
@@ -883,6 +883,25 @@ static bool opcode_allowed(struct mlx5_c
return cmd->allowed_opcode == opcode;
}
+static int cmd_alloc_index_retry(struct mlx5_cmd *cmd)
+{
+ unsigned long alloc_end = jiffies + msecs_to_jiffies(1000);
+ int idx;
+
+retry:
+ idx = cmd_alloc_index(cmd);
+ if (idx < 0 && time_before(jiffies, alloc_end)) {
+ /* Index allocation can fail on heavy load of commands. This is a temporary
+ * situation as the current command already holds the semaphore, meaning that
+ * another command completion is being handled and it is expected to release
+ * the entry index soon.
+ */
+ cpu_relax();
+ goto retry;
+ }
+ return idx;
+}
+
static void cmd_work_handler(struct work_struct *work)
{
struct mlx5_cmd_work_ent *ent = container_of(work, struct mlx5_cmd_work_ent, work);
@@ -900,7 +919,7 @@ static void cmd_work_handler(struct work
sem = ent->page_queue ? &cmd->pages_sem : &cmd->sem;
down(sem);
if (!ent->page_queue) {
- alloc_ret = cmd_alloc_index(cmd);
+ alloc_ret = cmd_alloc_index_retry(cmd);
if (alloc_ret < 0) {
mlx5_core_err(dev, "failed to allocate command entry\n");
if (ent->callback) {
next prev parent reply other threads:[~2020-11-20 11:09 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 11:03 [PATCH 5.4 00/17] 5.4.79-rc1 review Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 01/17] selftests/powerpc: rfi_flush: disable entry flush if present Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 02/17] powerpc/64s: flush L1D on kernel entry Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 03/17] powerpc/64s: flush L1D after user accesses Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 04/17] powerpc: Only include kup-radix.h for 64-bit Book3S Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 05/17] selftests/powerpc: entry flush test Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 06/17] MIPS: PCI: Fix MIPS build Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 07/17] net/mlx5: Use async EQ setup cleanup helpers for multiple EQs Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 08/17] net/mlx5: poll cmd EQ in case of command timeout Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 09/17] net/mlx5: Fix a race when moving command interface to events mode Greg Kroah-Hartman
2020-11-20 11:03 ` Greg Kroah-Hartman [this message]
2020-11-20 11:03 ` [PATCH 5.4 11/17] powerpc/8xx: Always fault when _PAGE_ACCESSED is not set Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 12/17] net: lantiq: Add locking for TX DMA channel Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 13/17] Input: sunkbd - avoid use-after-free in teardown paths Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 14/17] mac80211: always wind down STA state Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 15/17] can: proc: can_remove_proc(): silence remove_proc_entry warning Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 16/17] KVM: x86: clflushopt should be treated as a no-op by emulation Greg Kroah-Hartman
2020-11-20 11:03 ` [PATCH 5.4 17/17] ACPI: GED: fix -Wformat Greg Kroah-Hartman
2020-11-20 22:28 ` [PATCH 5.4 00/17] 5.4.79-rc1 review Shuah Khan
2020-11-21 11:48 ` Naresh Kamboju
2020-11-21 18:37 ` Guenter Roeck
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