From da8badd7d3583f447eac2ab65a332f2d773deca1 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 13 Jun 2022 14:44:40 -0700 Subject: scsi: ufs: Simplify ufshcd_clear_cmd() Remove the local variable 'err'. This patch does not change any functionality. Link: https://lore.kernel.org/r/20220613214442.212466-2-bvanassche@acm.org Reviewed-by: Stanley Chu Reviewed-by: Adrian Hunter Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/ufs/core/ufshcd.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'drivers/ufs') diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 01fb4bad86be..2d479e31c588 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -2866,7 +2866,6 @@ 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; @@ -2879,11 +2878,8 @@ 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 -- cgit v1.2.3 From d1a7644648b7cdacaf8d1013a4285001911e9bc8 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 13 Jun 2022 14:44:41 -0700 Subject: scsi: ufs: Support clearing multiple commands at once 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. Link: https://lore.kernel.org/r/20220613214442.212466-3-bvanassche@acm.org Reviewed-by: Stanley Chu Reviewed-by: Adrian Hunter Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/ufs/core/ufshcd.c | 42 ++++++++++++++++++++++++++++-------------- 1 file changed, 28 insertions(+), 14 deletions(-) (limited to 'drivers/ufs') diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 2d479e31c588..8789147760ae 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); } /** @@ -2863,15 +2874,18 @@ 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); /* @@ -2959,7 +2973,7 @@ 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; /* @@ -6982,7 +6996,7 @@ 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); @@ -7084,7 +7098,7 @@ 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); -- cgit v1.2.3 From 2acd76e7b8596e307fcec8fc6bc5fe5ab174749a Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 13 Jun 2022 14:44:42 -0700 Subject: scsi: ufs: Fix a race between the interrupt handler and the reset handler 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 Link: https://lore.kernel.org/r/20220613214442.212466-4-bvanassche@acm.org Reviewed-by: Stanley Chu Reviewed-by: Adrian Hunter Signed-off-by: Bart Van Assche Signed-off-by: Martin K. Petersen --- drivers/ufs/core/ufshcd.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-) (limited to 'drivers/ufs') diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 8789147760ae..ce86d1b790c0 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -6968,14 +6968,14 @@ 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; @@ -6994,14 +6994,24 @@ 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; -- cgit v1.2.3