From b4b7ff4b08e691656c9d77c758fc355833128ac0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 20 Jan 2016 14:01:31 -0300 Subject: Linux-libre 4.4-gnu --- drivers/scsi/cxlflash/superpipe.c | 209 ++++++++++++++++++++++++-------------- 1 file changed, 134 insertions(+), 75 deletions(-) (limited to 'drivers/scsi/cxlflash/superpipe.c') diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c index f1b62cea7..cac2e6a50 100644 --- a/drivers/scsi/cxlflash/superpipe.c +++ b/drivers/scsi/cxlflash/superpipe.c @@ -76,7 +76,7 @@ void cxlflash_free_errpage(void) * * When the host needs to go down, all users must be quiesced and their * memory freed. This is accomplished by putting the contexts in error - * state which will notify the user and let them 'drive' the tear-down. + * state which will notify the user and let them 'drive' the tear down. * Meanwhile, this routine camps until all user contexts have been removed. */ void cxlflash_stop_term_user_contexts(struct cxlflash_cfg *cfg) @@ -100,7 +100,7 @@ void cxlflash_stop_term_user_contexts(struct cxlflash_cfg *cfg) dev_dbg(dev, "%s: Wait for user contexts to quiesce...\n", __func__); - wake_up_all(&cfg->limbo_waitq); + wake_up_all(&cfg->reset_waitq); ssleep(1); } } @@ -162,10 +162,7 @@ struct ctx_info *get_context(struct cxlflash_cfg *cfg, u64 rctxid, if (likely(ctxid < MAX_CONTEXT)) { while (true) { - rc = mutex_lock_interruptible(&cfg->ctx_tbl_list_mutex); - if (rc) - goto out; - + mutex_lock(&cfg->ctx_tbl_list_mutex); ctxi = cfg->ctx_tbl[ctxid]; if (ctxi) if ((file && (ctxi->file != file)) || @@ -253,7 +250,7 @@ static int afu_attach(struct cxlflash_cfg *cfg, struct ctx_info *ctxi) { struct device *dev = &cfg->dev->dev; struct afu *afu = cfg->afu; - struct sisl_ctrl_map *ctrl_map = ctxi->ctrl_map; + struct sisl_ctrl_map __iomem *ctrl_map = ctxi->ctrl_map; int rc = 0; u64 val; @@ -283,6 +280,24 @@ out: * @sdev: SCSI device associated with LUN. * @lli: LUN destined for capacity request. * + * The READ_CAP16 can take quite a while to complete. Should an EEH occur while + * in scsi_execute(), the EEH handler will attempt to recover. As part of the + * recovery, the handler drains all currently running ioctls, waiting until they + * have completed before proceeding with a reset. As this routine is used on the + * ioctl path, this can create a condition where the EEH handler becomes stuck, + * infinitely waiting for this ioctl thread. To avoid this behavior, temporarily + * unmark this thread as an ioctl thread by releasing the ioctl read semaphore. + * This will allow the EEH handler to proceed with a recovery while this thread + * is still running. Once the scsi_execute() returns, reacquire the ioctl read + * semaphore and check the adapter state in case it changed while inside of + * scsi_execute(). The state check will wait if the adapter is still being + * recovered or return a failure if the recovery failed. In the event that the + * adapter reset failed, simply return the failure as the ioctl would be unable + * to continue. + * + * Note that the above puts a requirement on this routine to only be called on + * an ioctl thread. + * * Return: 0 on success, -errno on failure */ static int read_cap16(struct scsi_device *sdev, struct llun_info *lli) @@ -296,7 +311,7 @@ static int read_cap16(struct scsi_device *sdev, struct llun_info *lli) int rc = 0; int result = 0; int retry_cnt = 0; - u32 tout = (MC_DISCOVERY_TIMEOUT * HZ); + u32 to = CMD_TIMEOUT * HZ; retry: cmd_buf = kzalloc(CMD_BUFSIZE, GFP_KERNEL); @@ -314,8 +329,18 @@ retry: dev_dbg(dev, "%s: %ssending cmd(0x%x)\n", __func__, retry_cnt ? "re" : "", scsi_cmd[0]); + /* Drop the ioctl read semahpore across lengthy call */ + up_read(&cfg->ioctl_rwsem); result = scsi_execute(sdev, scsi_cmd, DMA_FROM_DEVICE, cmd_buf, - CMD_BUFSIZE, sense_buf, tout, 5, 0, NULL); + CMD_BUFSIZE, sense_buf, to, CMD_RETRIES, 0, NULL); + down_read(&cfg->ioctl_rwsem); + rc = check_state(cfg); + if (rc) { + dev_err(dev, "%s: Failed state! result=0x08%X\n", + __func__, result); + rc = -ENODEV; + goto out; + } if (driver_byte(result) == DRIVER_SENSE) { result &= ~(0xFF<<24); /* DRIVER_SENSE is not an error */ @@ -365,8 +390,8 @@ retry: * as the buffer is allocated on an aligned boundary. */ mutex_lock(&gli->mutex); - gli->max_lba = be64_to_cpu(*((u64 *)&cmd_buf[0])); - gli->blk_len = be32_to_cpu(*((u32 *)&cmd_buf[8])); + gli->max_lba = be64_to_cpu(*((__be64 *)&cmd_buf[0])); + gli->blk_len = be32_to_cpu(*((__be32 *)&cmd_buf[8])); mutex_unlock(&gli->mutex); out: @@ -712,7 +737,6 @@ static void destroy_context(struct cxlflash_cfg *cfg, kfree(ctxi->rht_needs_ws); kfree(ctxi->rht_lun); kfree(ctxi); - atomic_dec_if_positive(&cfg->num_user_contexts); } /** @@ -737,7 +761,7 @@ static struct ctx_info *create_context(struct cxlflash_cfg *cfg, struct afu *afu = cfg->afu; struct ctx_info *ctxi = NULL; struct llun_info **lli = NULL; - bool *ws = NULL; + u8 *ws = NULL; struct sisl_rht_entry *rhte; ctxi = kzalloc(sizeof(*ctxi), GFP_KERNEL); @@ -769,7 +793,6 @@ static struct ctx_info *create_context(struct cxlflash_cfg *cfg, INIT_LIST_HEAD(&ctxi->luns); INIT_LIST_HEAD(&ctxi->list); /* initialize for list_empty() */ - atomic_inc(&cfg->num_user_contexts); mutex_lock(&ctxi->mutex); out: return ctxi; @@ -880,6 +903,9 @@ static int _cxlflash_disk_detach(struct scsi_device *sdev, sys_close(lfd); } + /* Release the sdev reference that bound this LUN to the context */ + scsi_device_put(sdev); + out: if (put_ctx) put_context(ctxi); @@ -1161,10 +1187,7 @@ out: return rc; } -/* - * Local fops for adapter file descriptor - */ -static const struct file_operations cxlflash_cxl_fops = { +const struct file_operations cxlflash_cxl_fops = { .owner = THIS_MODULE, .mmap = cxlflash_cxl_mmap, .release = cxlflash_cxl_release, @@ -1210,6 +1233,46 @@ static const struct file_operations null_fops = { .owner = THIS_MODULE, }; +/** + * check_state() - checks and responds to the current adapter state + * @cfg: Internal structure associated with the host. + * + * This routine can block and should only be used on process context. + * It assumes that the caller is an ioctl thread and holding the ioctl + * read semaphore. This is temporarily let up across the wait to allow + * for draining actively running ioctls. Also note that when waking up + * from waiting in reset, the state is unknown and must be checked again + * before proceeding. + * + * Return: 0 on success, -errno on failure + */ +int check_state(struct cxlflash_cfg *cfg) +{ + struct device *dev = &cfg->dev->dev; + int rc = 0; + +retry: + switch (cfg->state) { + case STATE_RESET: + dev_dbg(dev, "%s: Reset state, going to wait...\n", __func__); + up_read(&cfg->ioctl_rwsem); + rc = wait_event_interruptible(cfg->reset_waitq, + cfg->state != STATE_RESET); + down_read(&cfg->ioctl_rwsem); + if (unlikely(rc)) + break; + goto retry; + case STATE_FAILTERM: + dev_dbg(dev, "%s: Failed/Terminating!\n", __func__); + rc = -ENODEV; + break; + default: + break; + } + + return rc; +} + /** * cxlflash_disk_attach() - attach a LUN to a context * @sdev: SCSI device associated with LUN. @@ -1243,10 +1306,6 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, int fd = -1; - /* On first attach set fileops */ - if (atomic_read(&cfg->num_user_contexts) == 0) - cfg->cxl_fops = cxlflash_cxl_fops; - if (attach->num_interrupts > 4) { dev_dbg(dev, "%s: Cannot support this many interrupts %llu\n", __func__, attach->num_interrupts); @@ -1287,11 +1346,17 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, } } + rc = scsi_device_get(sdev); + if (unlikely(rc)) { + dev_err(dev, "%s: Unable to get sdev reference!\n", __func__); + goto out; + } + lun_access = kzalloc(sizeof(*lun_access), GFP_KERNEL); if (unlikely(!lun_access)) { dev_err(dev, "%s: Unable to allocate lun_access!\n", __func__); rc = -ENOMEM; - goto out; + goto err0; } lun_access->lli = lli; @@ -1311,21 +1376,21 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, dev_err(dev, "%s: Could not initialize context %p\n", __func__, ctx); rc = -ENODEV; - goto err0; + goto err1; } ctxid = cxl_process_element(ctx); if (unlikely((ctxid > MAX_CONTEXT) || (ctxid < 0))) { dev_err(dev, "%s: ctxid (%d) invalid!\n", __func__, ctxid); rc = -EPERM; - goto err1; + goto err2; } file = cxl_get_fd(ctx, &cfg->cxl_fops, &fd); if (unlikely(fd < 0)) { rc = -ENODEV; dev_err(dev, "%s: Could not get file descriptor\n", __func__); - goto err1; + goto err2; } /* Translate read/write O_* flags from fcntl.h to AFU permission bits */ @@ -1335,7 +1400,7 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, if (unlikely(!ctxi)) { dev_err(dev, "%s: Failed to create context! (%d)\n", __func__, ctxid); - goto err2; + goto err3; } work = &ctxi->work; @@ -1346,13 +1411,13 @@ static int cxlflash_disk_attach(struct scsi_device *sdev, if (unlikely(rc)) { dev_dbg(dev, "%s: Could not start context rc=%d\n", __func__, rc); - goto err3; + goto err4; } rc = afu_attach(cfg, ctxi); if (unlikely(rc)) { dev_err(dev, "%s: Could not attach AFU rc %d\n", __func__, rc); - goto err4; + goto err5; } /* @@ -1375,7 +1440,8 @@ out_attach: attach->block_size = gli->blk_len; attach->mmio_size = sizeof(afu->afu_map->hosts[0].harea); attach->last_lba = gli->max_lba; - attach->max_xfer = (sdev->host->max_sectors * 512) / gli->blk_len; + attach->max_xfer = sdev->host->max_sectors * MAX_SECTOR_UNIT; + attach->max_xfer /= gli->blk_len; out: attach->adap_fd = fd; @@ -1387,13 +1453,13 @@ out: __func__, ctxid, fd, attach->block_size, rc, attach->last_lba); return rc; -err4: +err5: cxl_stop_context(ctx); -err3: +err4: put_context(ctxi); destroy_context(cfg, ctxi); ctxi = NULL; -err2: +err3: /* * Here, we're overriding the fops with a dummy all-NULL fops because * fput() calls the release fop, which will cause us to mistakenly @@ -1405,10 +1471,12 @@ err2: fput(file); put_unused_fd(fd); fd = -1; -err1: +err2: cxl_release_context(ctx); -err0: +err1: kfree(lun_access); +err0: + scsi_device_put(sdev); goto out; } @@ -1510,41 +1578,6 @@ err1: goto out; } -/** - * check_state() - checks and responds to the current adapter state - * @cfg: Internal structure associated with the host. - * - * This routine can block and should only be used on process context. - * Note that when waking up from waiting in limbo, the state is unknown - * and must be checked again before proceeding. - * - * Return: 0 on success, -errno on failure - */ -static int check_state(struct cxlflash_cfg *cfg) -{ - struct device *dev = &cfg->dev->dev; - int rc = 0; - -retry: - switch (cfg->state) { - case STATE_LIMBO: - dev_dbg(dev, "%s: Limbo, going to wait...\n", __func__); - rc = wait_event_interruptible(cfg->limbo_waitq, - cfg->state != STATE_LIMBO); - if (unlikely(rc)) - break; - goto retry; - case STATE_FAILTERM: - dev_dbg(dev, "%s: Failed/Terminating!\n", __func__); - rc = -ENODEV; - break; - default: - break; - } - - return rc; -} - /** * cxlflash_afu_recover() - initiates AFU recovery * @sdev: SCSI device associated with LUN. @@ -1561,10 +1594,10 @@ retry: * quite possible for this routine to act as the kernel's EEH detection * source (MMIO read of mbox_r). Because of this, there is a window of * time where an EEH might have been detected but not yet 'serviced' - * (callback invoked, causing the device to enter limbo state). To avoid + * (callback invoked, causing the device to enter reset state). To avoid * looping in this routine during that window, a 1 second sleep is in place * between the time the MMIO failure is detected and the time a wait on the - * limbo wait queue is attempted via check_state(). + * reset wait queue is attempted via check_state(). * * Return: 0 on success, -errno on failure */ @@ -1634,9 +1667,14 @@ retry_recover: /* Test if in error state */ reg = readq_be(&afu->ctrl_map->mbox_r); if (reg == -1) { - dev_dbg(dev, "%s: MMIO read fail! Wait for recovery...\n", - __func__); - mutex_unlock(&ctxi->mutex); + dev_dbg(dev, "%s: MMIO fail, wait for recovery.\n", __func__); + + /* + * Before checking the state, put back the context obtained with + * get_context() as it is no longer needed and sleep for a short + * period of time (see prolog notes). + */ + put_context(ctxi); ctxi = NULL; ssleep(1); rc = check_state(cfg); @@ -1765,12 +1803,21 @@ static int cxlflash_disk_verify(struct scsi_device *sdev, * inquiry (i.e. the Unit attention is due to the WWN changing). */ if (verify->hint & DK_CXLFLASH_VERIFY_HINT_SENSE) { + /* Can't hold mutex across process_sense/read_cap16, + * since we could have an intervening EEH event. + */ + ctxi->unavail = true; + mutex_unlock(&ctxi->mutex); rc = process_sense(sdev, verify); if (unlikely(rc)) { dev_err(dev, "%s: Failed to validate sense data (%d)\n", __func__, rc); + mutex_lock(&ctxi->mutex); + ctxi->unavail = false; goto out; } + mutex_lock(&ctxi->mutex); + ctxi->unavail = false; } switch (gli->mode) { @@ -1955,6 +2002,14 @@ out: * @cmd: IOCTL command. * @arg: Userspace ioctl data structure. * + * A read/write semaphore is used to implement a 'drain' of currently + * running ioctls. The read semaphore is taken at the beginning of each + * ioctl thread and released upon concluding execution. Additionally the + * semaphore should be released and then reacquired in any ioctl execution + * path which will wait for an event to occur that is outside the scope of + * the ioctl (i.e. an adapter reset). To drain the ioctls currently running, + * a thread simply needs to acquire the write semaphore. + * * Return: 0 on success, -errno on failure */ int cxlflash_ioctl(struct scsi_device *sdev, int cmd, void __user *arg) @@ -1989,6 +2044,9 @@ int cxlflash_ioctl(struct scsi_device *sdev, int cmd, void __user *arg) {sizeof(struct dk_cxlflash_clone), (sioctl)cxlflash_disk_clone}, }; + /* Hold read semaphore so we can drain if needed */ + down_read(&cfg->ioctl_rwsem); + /* Restrict command set to physical support only for internal LUN */ if (afu->internal_lun) switch (cmd) { @@ -2070,6 +2128,7 @@ int cxlflash_ioctl(struct scsi_device *sdev, int cmd, void __user *arg) /* fall through to exit */ cxlflash_ioctl_exit: + up_read(&cfg->ioctl_rwsem); if (unlikely(rc && known_ioctl)) dev_err(dev, "%s: ioctl %s (%08X) on dev(%d/%d/%d/%llu) " "returned rc %d\n", __func__, -- cgit v1.2.3-54-g00ecf