* [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler
@ 2022-06-13 21:44 Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 1/3] scsi: ufs: Simplify ufshcd_clear_cmd() Bart Van Assche
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: Bart Van Assche @ 2022-06-13 21:44 UTC (permalink / raw)
To: Martin K . Petersen
Cc: Jaegeuk Kim, Adrian Hunter, linux-scsi, Bart Van Assche
Hi Martin,
This patch series is version two of a fix between the UFS interrupt handler and
reset handlers. Please consider this patch series for kernel v5.20.
Changes compared to v1:
- Converted a single patch into three patches.
- Modified patch 3/3 such that only cleared requests are completed.
Bart Van Assche (3):
scsi: ufs: Simplify ufshcd_clear_cmd()
scsi: ufs: Support clearing multiple commands at once
scsi: ufs: Fix a race between the interrupt handler and the reset
handler
drivers/ufs/core/ufshcd.c | 76 ++++++++++++++++++++++++---------------
1 file changed, 48 insertions(+), 28 deletions(-)
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 1/3] scsi: ufs: Simplify ufshcd_clear_cmd()
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
@ 2022-06-13 21:44 ` Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 2/3] scsi: ufs: Support clearing multiple commands at once Bart Van Assche
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Bart Van Assche @ 2022-06-13 21:44 UTC (permalink / raw)
To: Martin K . Petersen
Cc: Jaegeuk Kim, Adrian Hunter, linux-scsi, Bart Van Assche,
James E.J. Bottomley, Bean Huo, Avri Altman, Daejun Park
Remove the local variable 'err'. This patch does not change any
functionality.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/ufs/core/ufshcd.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index bb6cbd514a69..4ed2f6c29e80 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -2868,7 +2868,6 @@ static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
static int
ufshcd_clear_cmd(struct ufs_hba *hba, int tag)
{
- int err = 0;
unsigned long flags;
u32 mask = 1 << tag;
@@ -2881,11 +2880,8 @@ ufshcd_clear_cmd(struct ufs_hba *hba, int tag)
* wait for h/w to clear corresponding bit in door-bell.
* max. wait is 1 sec.
*/
- err = ufshcd_wait_for_register(hba,
- REG_UTP_TRANSFER_REQ_DOOR_BELL,
- mask, ~mask, 1000, 1000);
-
- return err;
+ return ufshcd_wait_for_register(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL,
+ mask, ~mask, 1000, 1000);
}
static int
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v2 2/3] scsi: ufs: Support clearing multiple commands at once
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 1/3] scsi: ufs: Simplify ufshcd_clear_cmd() Bart Van Assche
@ 2022-06-13 21:44 ` Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 3/3] scsi: ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Bart Van Assche @ 2022-06-13 21:44 UTC (permalink / raw)
To: Martin K . Petersen
Cc: Jaegeuk Kim, Adrian Hunter, linux-scsi, Bart Van Assche,
James E.J. Bottomley, Bean Huo, Avri Altman, Daejun Park
Modify ufshcd_clear_cmd() such that it supports clearing multiple
commands at once instead of one command at a time. This change will be
used in a later patch to reduce the time spent in the reset handler.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/ufs/core/ufshcd.c | 42 ++++++++++++++++++++++++++-------------
1 file changed, 28 insertions(+), 14 deletions(-)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 4ed2f6c29e80..b7120c5f0920 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -748,17 +748,28 @@ static enum utp_ocs ufshcd_get_tr_ocs(struct ufshcd_lrb *lrbp)
}
/**
- * ufshcd_utrl_clear - Clear a bit in UTRLCLR register
+ * ufshcd_utrl_clear() - Clear requests from the controller request list.
* @hba: per adapter instance
- * @pos: position of the bit to be cleared
+ * @mask: mask with one bit set for each request to be cleared
*/
-static inline void ufshcd_utrl_clear(struct ufs_hba *hba, u32 pos)
+static inline void ufshcd_utrl_clear(struct ufs_hba *hba, u32 mask)
{
if (hba->quirks & UFSHCI_QUIRK_BROKEN_REQ_LIST_CLR)
- ufshcd_writel(hba, (1 << pos), REG_UTP_TRANSFER_REQ_LIST_CLEAR);
- else
- ufshcd_writel(hba, ~(1 << pos),
- REG_UTP_TRANSFER_REQ_LIST_CLEAR);
+ mask = ~mask;
+ /*
+ * From the UFSHCI specification: "UTP Transfer Request List CLear
+ * Register (UTRLCLR): This field is bit significant. Each bit
+ * corresponds to a slot in the UTP Transfer Request List, where bit 0
+ * corresponds to request slot 0. A bit in this field is set to ‘0’
+ * by host software to indicate to the host controller that a transfer
+ * request slot is cleared. The host controller
+ * shall free up any resources associated to the request slot
+ * immediately, and shall set the associated bit in UTRLDBR to ‘0’. The
+ * host software indicates no change to request slots by setting the
+ * associated bits in this field to ‘1’. Bits in this field shall only
+ * be set ‘1’ or ‘0’ by host software when UTRLRSR is set to ‘1’."
+ */
+ ufshcd_writel(hba, ~mask, REG_UTP_TRANSFER_REQ_LIST_CLEAR);
}
/**
@@ -2865,15 +2876,18 @@ static int ufshcd_compose_dev_cmd(struct ufs_hba *hba,
return ufshcd_compose_devman_upiu(hba, lrbp);
}
-static int
-ufshcd_clear_cmd(struct ufs_hba *hba, int tag)
+/*
+ * Clear all the requests from the controller for which a bit has been set in
+ * @mask and wait until the controller confirms that these requests have been
+ * cleared.
+ */
+static int ufshcd_clear_cmds(struct ufs_hba *hba, u32 mask)
{
unsigned long flags;
- u32 mask = 1 << tag;
/* clear outstanding transaction before retry */
spin_lock_irqsave(hba->host->host_lock, flags);
- ufshcd_utrl_clear(hba, tag);
+ ufshcd_utrl_clear(hba, mask);
spin_unlock_irqrestore(hba->host->host_lock, flags);
/*
@@ -2961,7 +2975,7 @@ static int ufshcd_wait_for_dev_cmd(struct ufs_hba *hba,
err = -ETIMEDOUT;
dev_dbg(hba->dev, "%s: dev_cmd request timedout, tag %d\n",
__func__, lrbp->task_tag);
- if (!ufshcd_clear_cmd(hba, lrbp->task_tag))
+ if (!ufshcd_clear_cmds(hba, 1U << lrbp->task_tag))
/* successfully cleared the command, retry if needed */
err = -EAGAIN;
/*
@@ -6989,7 +7003,7 @@ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
/* clear the commands that were pending for corresponding LUN */
for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs) {
if (hba->lrb[pos].lun == lun) {
- err = ufshcd_clear_cmd(hba, pos);
+ err = ufshcd_clear_cmds(hba, 1U << pos);
if (err)
break;
__ufshcd_transfer_req_compl(hba, 1U << pos);
@@ -7091,7 +7105,7 @@ static int ufshcd_try_to_abort_task(struct ufs_hba *hba, int tag)
goto out;
}
- err = ufshcd_clear_cmd(hba, tag);
+ err = ufshcd_clear_cmds(hba, 1U << tag);
if (err)
dev_err(hba->dev, "%s: Failed clearing cmd at tag %d, err %d\n",
__func__, tag, err);
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v2 3/3] scsi: ufs: Fix a race between the interrupt handler and the reset handler
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 1/3] scsi: ufs: Simplify ufshcd_clear_cmd() Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 2/3] scsi: ufs: Support clearing multiple commands at once Bart Van Assche
@ 2022-06-13 21:44 ` Bart Van Assche
2022-06-14 2:23 ` [PATCH v2 0/3] " Stanley Chu
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Bart Van Assche @ 2022-06-13 21:44 UTC (permalink / raw)
To: Martin K . Petersen
Cc: Jaegeuk Kim, Adrian Hunter, linux-scsi, Bart Van Assche,
James E.J. Bottomley, Bean Huo, Avri Altman
Prevent that both the interrupt handler and the reset handler try to
complete a request at the same time. This patch is the result of an
analysis of the following crash:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000120
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G OE 5.10.107-android13-4-00051-g1e48e8970cca-ab8664745 #1
pc : ufshcd_release_scsi_cmd+0x30/0x46c
lr : __ufshcd_transfer_req_compl+0x4fc/0x9c0
Call trace:
ufshcd_release_scsi_cmd+0x30/0x46c
__ufshcd_transfer_req_compl+0x4fc/0x9c0
ufshcd_poll+0xf0/0x208
ufshcd_sl_intr+0xb8/0xf0
ufshcd_intr+0x168/0x2f4
__handle_irq_event_percpu+0xa0/0x30c
handle_irq_event+0x84/0x178
handle_fasteoi_irq+0x150/0x2e8
__handle_domain_irq+0x114/0x1e4
gic_handle_irq.31846+0x58/0x300
el1_irq+0xe4/0x1c0
cpuidle_enter_state+0x3ac/0x8c4
do_idle+0x2fc/0x55c
cpu_startup_entry+0x84/0x90
kernel_init+0x0/0x310
start_kernel+0x0/0x608
start_kernel+0x4ec/0x608
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/ufs/core/ufshcd.c | 28 +++++++++++++++++++---------
1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index b7120c5f0920..ff3abda91bb6 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -6975,14 +6975,14 @@ int ufshcd_exec_raw_upiu_cmd(struct ufs_hba *hba,
}
/**
- * ufshcd_eh_device_reset_handler - device reset handler registered to
- * scsi layer.
+ * ufshcd_eh_device_reset_handler() - Reset a single logical unit.
* @cmd: SCSI command pointer
*
* Returns SUCCESS/FAILED
*/
static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
{
+ unsigned long flags, pending_reqs = 0, not_cleared = 0;
struct Scsi_Host *host;
struct ufs_hba *hba;
u32 pos;
@@ -7001,14 +7001,24 @@ static int ufshcd_eh_device_reset_handler(struct scsi_cmnd *cmd)
}
/* clear the commands that were pending for corresponding LUN */
- for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs) {
- if (hba->lrb[pos].lun == lun) {
- err = ufshcd_clear_cmds(hba, 1U << pos);
- if (err)
- break;
- __ufshcd_transfer_req_compl(hba, 1U << pos);
- }
+ spin_lock_irqsave(&hba->outstanding_lock, flags);
+ for_each_set_bit(pos, &hba->outstanding_reqs, hba->nutrs)
+ if (hba->lrb[pos].lun == lun)
+ __set_bit(pos, &pending_reqs);
+ hba->outstanding_reqs &= ~pending_reqs;
+ spin_unlock_irqrestore(&hba->outstanding_lock, flags);
+
+ if (ufshcd_clear_cmds(hba, pending_reqs) < 0) {
+ spin_lock_irqsave(&hba->outstanding_lock, flags);
+ not_cleared = pending_reqs &
+ ufshcd_readl(hba, REG_UTP_TRANSFER_REQ_DOOR_BELL);
+ hba->outstanding_reqs |= not_cleared;
+ spin_unlock_irqrestore(&hba->outstanding_lock, flags);
+
+ dev_err(hba->dev, "%s: failed to clear requests %#lx\n",
+ __func__, not_cleared);
}
+ __ufshcd_transfer_req_compl(hba, pending_reqs & ~not_cleared);
out:
hba->req_abort_count = 0;
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
` (2 preceding siblings ...)
2022-06-13 21:44 ` [PATCH v2 3/3] scsi: ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
@ 2022-06-14 2:23 ` Stanley Chu
2022-06-14 6:51 ` Adrian Hunter
2022-06-17 2:20 ` Martin K. Petersen
5 siblings, 0 replies; 7+ messages in thread
From: Stanley Chu @ 2022-06-14 2:23 UTC (permalink / raw)
To: Bart Van Assche, Martin K . Petersen
Cc: Jaegeuk Kim, Adrian Hunter, linux-scsi
Hi Bart,
I am not sure if this series could solve the racing you met.
However this series looks good to me.
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
On Mon, 2022-06-13 at 14:44 -0700, Bart Van Assche wrote:
> Hi Martin,
>
> This patch series is version two of a fix between the UFS interrupt
> handler and
> reset handlers. Please consider this patch series for kernel v5.20.
>
> Changes compared to v1:
> - Converted a single patch into three patches.
> - Modified patch 3/3 such that only cleared requests are completed.
>
> Bart Van Assche (3):
> scsi: ufs: Simplify ufshcd_clear_cmd()
> scsi: ufs: Support clearing multiple commands at once
> scsi: ufs: Fix a race between the interrupt handler and the reset
> handler
>
> drivers/ufs/core/ufshcd.c | 76 ++++++++++++++++++++++++-------------
> --
> 1 file changed, 48 insertions(+), 28 deletions(-)
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
` (3 preceding siblings ...)
2022-06-14 2:23 ` [PATCH v2 0/3] " Stanley Chu
@ 2022-06-14 6:51 ` Adrian Hunter
2022-06-17 2:20 ` Martin K. Petersen
5 siblings, 0 replies; 7+ messages in thread
From: Adrian Hunter @ 2022-06-14 6:51 UTC (permalink / raw)
To: Bart Van Assche, Martin K . Petersen; +Cc: Jaegeuk Kim, linux-scsi
On 14/06/22 00:44, Bart Van Assche wrote:
> Hi Martin,
>
> This patch series is version two of a fix between the UFS interrupt handler and
> reset handlers. Please consider this patch series for kernel v5.20.
>
> Changes compared to v1:
> - Converted a single patch into three patches.
> - Modified patch 3/3 such that only cleared requests are completed.
>
> Bart Van Assche (3):
> scsi: ufs: Simplify ufshcd_clear_cmd()
> scsi: ufs: Support clearing multiple commands at once
> scsi: ufs: Fix a race between the interrupt handler and the reset
> handler
>
> drivers/ufs/core/ufshcd.c | 76 ++++++++++++++++++++++++---------------
> 1 file changed, 48 insertions(+), 28 deletions(-)
>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
` (4 preceding siblings ...)
2022-06-14 6:51 ` Adrian Hunter
@ 2022-06-17 2:20 ` Martin K. Petersen
5 siblings, 0 replies; 7+ messages in thread
From: Martin K. Petersen @ 2022-06-17 2:20 UTC (permalink / raw)
To: Bart Van Assche
Cc: Martin K . Petersen, linux-scsi, Adrian Hunter, Jaegeuk Kim
On Mon, 13 Jun 2022 14:44:39 -0700, Bart Van Assche wrote:
> This patch series is version two of a fix between the UFS interrupt handler and
> reset handlers. Please consider this patch series for kernel v5.20.
>
> Changes compared to v1:
> - Converted a single patch into three patches.
> - Modified patch 3/3 such that only cleared requests are completed.
>
> [...]
Applied to 5.19/scsi-fixes, thanks!
[1/3] scsi: ufs: Simplify ufshcd_clear_cmd()
https://git.kernel.org/mkp/scsi/c/da8badd7d358
[2/3] scsi: ufs: Support clearing multiple commands at once
https://git.kernel.org/mkp/scsi/c/d1a7644648b7
[3/3] scsi: ufs: Fix a race between the interrupt handler and the reset handler
https://git.kernel.org/mkp/scsi/c/2acd76e7b859
--
Martin K. Petersen Oracle Linux Engineering
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-06-17 2:20 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-06-13 21:44 [PATCH v2 0/3] ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 1/3] scsi: ufs: Simplify ufshcd_clear_cmd() Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 2/3] scsi: ufs: Support clearing multiple commands at once Bart Van Assche
2022-06-13 21:44 ` [PATCH v2 3/3] scsi: ufs: Fix a race between the interrupt handler and the reset handler Bart Van Assche
2022-06-14 2:23 ` [PATCH v2 0/3] " Stanley Chu
2022-06-14 6:51 ` Adrian Hunter
2022-06-17 2:20 ` Martin K. Petersen
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.