From fb51ccbf217c1c994607b6519c7d85250928553d Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Fri, 4 Nov 2011 09:45:59 +0100 Subject: PCI: Rework config space blocking services pci_block_user_cfg_access was designed for the use case that a single context, the IPR driver, temporarily delays user space accesses to the config space via sysfs. This assumption became invalid by the time pci_dev_reset was added as locking instance. Today, if you run two loops in parallel that reset the same device via sysfs, you end up with a kernel BUG as pci_block_user_cfg_access detect the broken assumption. This reworks the pci_block_user_cfg_access to a sleeping service pci_cfg_access_lock and an atomic-compatible variant called pci_cfg_access_trylock. The former not only blocks user space access as before but also waits if access was already locked. The latter service just returns false in this case, allowing the caller to resolve the conflict instead of raising a BUG. Adaptions of the ipr driver were originally written by Brian King. Acked-by: Brian King Acked-by: Michael S. Tsirkin Signed-off-by: Jan Kiszka Signed-off-by: Jesse Barnes --- drivers/scsi/ipr.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 60 insertions(+), 7 deletions(-) (limited to 'drivers/scsi/ipr.c') diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c index fd860d952b28..67b169b7a5be 100644 --- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -7638,8 +7638,12 @@ static int ipr_reset_restore_cfg_space(struct ipr_cmnd *ipr_cmd) **/ static int ipr_reset_bist_done(struct ipr_cmnd *ipr_cmd) { + struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg; + ENTER; - pci_unblock_user_cfg_access(ipr_cmd->ioa_cfg->pdev); + if (ioa_cfg->cfg_locked) + pci_cfg_access_unlock(ioa_cfg->pdev); + ioa_cfg->cfg_locked = 0; ipr_cmd->job_step = ipr_reset_restore_cfg_space; LEAVE; return IPR_RC_JOB_CONTINUE; @@ -7660,8 +7664,6 @@ static int ipr_reset_start_bist(struct ipr_cmnd *ipr_cmd) int rc = PCIBIOS_SUCCESSFUL; ENTER; - pci_block_user_cfg_access(ioa_cfg->pdev); - if (ioa_cfg->ipr_chip->bist_method == IPR_MMIO) writel(IPR_UPROCI_SIS64_START_BIST, ioa_cfg->regs.set_uproc_interrupt_reg32); @@ -7673,7 +7675,9 @@ static int ipr_reset_start_bist(struct ipr_cmnd *ipr_cmd) ipr_reset_start_timer(ipr_cmd, IPR_WAIT_FOR_BIST_TIMEOUT); rc = IPR_RC_JOB_RETURN; } else { - pci_unblock_user_cfg_access(ipr_cmd->ioa_cfg->pdev); + if (ioa_cfg->cfg_locked) + pci_cfg_access_unlock(ipr_cmd->ioa_cfg->pdev); + ioa_cfg->cfg_locked = 0; ipr_cmd->s.ioasa.hdr.ioasc = cpu_to_be32(IPR_IOASC_PCI_ACCESS_ERROR); rc = IPR_RC_JOB_CONTINUE; } @@ -7716,7 +7720,6 @@ static int ipr_reset_slot_reset(struct ipr_cmnd *ipr_cmd) struct pci_dev *pdev = ioa_cfg->pdev; ENTER; - pci_block_user_cfg_access(pdev); pci_set_pcie_reset_state(pdev, pcie_warm_reset); ipr_cmd->job_step = ipr_reset_slot_reset_done; ipr_reset_start_timer(ipr_cmd, IPR_PCI_RESET_TIMEOUT); @@ -7724,6 +7727,56 @@ static int ipr_reset_slot_reset(struct ipr_cmnd *ipr_cmd) return IPR_RC_JOB_RETURN; } +/** + * ipr_reset_block_config_access_wait - Wait for permission to block config access + * @ipr_cmd: ipr command struct + * + * Description: This attempts to block config access to the IOA. + * + * Return value: + * IPR_RC_JOB_CONTINUE / IPR_RC_JOB_RETURN + **/ +static int ipr_reset_block_config_access_wait(struct ipr_cmnd *ipr_cmd) +{ + struct ipr_ioa_cfg *ioa_cfg = ipr_cmd->ioa_cfg; + int rc = IPR_RC_JOB_CONTINUE; + + if (pci_cfg_access_trylock(ioa_cfg->pdev)) { + ioa_cfg->cfg_locked = 1; + ipr_cmd->job_step = ioa_cfg->reset; + } else { + if (ipr_cmd->u.time_left) { + rc = IPR_RC_JOB_RETURN; + ipr_cmd->u.time_left -= IPR_CHECK_FOR_RESET_TIMEOUT; + ipr_reset_start_timer(ipr_cmd, + IPR_CHECK_FOR_RESET_TIMEOUT); + } else { + ipr_cmd->job_step = ioa_cfg->reset; + dev_err(&ioa_cfg->pdev->dev, + "Timed out waiting to lock config access. Resetting anyway.\n"); + } + } + + return rc; +} + +/** + * ipr_reset_block_config_access - Block config access to the IOA + * @ipr_cmd: ipr command struct + * + * Description: This attempts to block config access to the IOA + * + * Return value: + * IPR_RC_JOB_CONTINUE + **/ +static int ipr_reset_block_config_access(struct ipr_cmnd *ipr_cmd) +{ + ipr_cmd->ioa_cfg->cfg_locked = 0; + ipr_cmd->job_step = ipr_reset_block_config_access_wait; + ipr_cmd->u.time_left = IPR_WAIT_FOR_RESET_TIMEOUT; + return IPR_RC_JOB_CONTINUE; +} + /** * ipr_reset_allowed - Query whether or not IOA can be reset * @ioa_cfg: ioa config struct @@ -7763,7 +7816,7 @@ static int ipr_reset_wait_to_start_bist(struct ipr_cmnd *ipr_cmd) ipr_cmd->u.time_left -= IPR_CHECK_FOR_RESET_TIMEOUT; ipr_reset_start_timer(ipr_cmd, IPR_CHECK_FOR_RESET_TIMEOUT); } else { - ipr_cmd->job_step = ioa_cfg->reset; + ipr_cmd->job_step = ipr_reset_block_config_access; rc = IPR_RC_JOB_CONTINUE; } @@ -7796,7 +7849,7 @@ static int ipr_reset_alert(struct ipr_cmnd *ipr_cmd) writel(IPR_UPROCI_RESET_ALERT, ioa_cfg->regs.set_uproc_interrupt_reg32); ipr_cmd->job_step = ipr_reset_wait_to_start_bist; } else { - ipr_cmd->job_step = ioa_cfg->reset; + ipr_cmd->job_step = ipr_reset_block_config_access; } ipr_cmd->u.time_left = IPR_WAIT_FOR_RESET_TIMEOUT; -- cgit v1.2.3 From a92fa25c63a788758bd52e9123504d133210c8b7 Mon Sep 17 00:00:00 2001 From: Kleber Sacilotto de Souza Date: Mon, 16 Jan 2012 19:30:25 -0200 Subject: [SCSI] ipr: fix eeh recovery for 64-bit adapters In some scenarios, an EEH error can take a long time to be detected, since the driver issues an MMIO read only after a device reset command times out and we try to reset the adapter. This patch adds some code in ipr_cancel_op() to read a hardware register so we detect the error earlier in case the op is being aborted because of a timeout caused by a frozen adapter slot. Another problem in such scenarios is that in __ipr_eh_host_reset() we change the dump state flag from WAIT_FOR_DUMP to GET_DUMP, and the flag is later changed from GET_DUMP to READ_DUMP in ipr_reset_restore_cfg_space(). However, if when __ipr_eh_host_reset() is called by the SCSI error handling the function ipr_reset_restore_cfg_space() has already been called by the PCI EEH code, we end up with the flag in an inconsistent state. This patch also prevents this problem. Signed-off-by: Kleber Sacilotto de Souza Acked-by: Brian King Signed-off-by: James Bottomley --- drivers/scsi/ipr.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) (limited to 'drivers/scsi/ipr.c') diff --git a/drivers/scsi/ipr.c b/drivers/scsi/ipr.c index 67b169b7a5be..b538f0883fd2 100644 --- a/drivers/scsi/ipr.c +++ b/drivers/scsi/ipr.c @@ -4613,11 +4613,13 @@ static int __ipr_eh_host_reset(struct scsi_cmnd * scsi_cmd) ENTER; ioa_cfg = (struct ipr_ioa_cfg *) scsi_cmd->device->host->hostdata; - dev_err(&ioa_cfg->pdev->dev, - "Adapter being reset as a result of error recovery.\n"); + if (!ioa_cfg->in_reset_reload) { + dev_err(&ioa_cfg->pdev->dev, + "Adapter being reset as a result of error recovery.\n"); - if (WAIT_FOR_DUMP == ioa_cfg->sdt_state) - ioa_cfg->sdt_state = GET_DUMP; + if (WAIT_FOR_DUMP == ioa_cfg->sdt_state) + ioa_cfg->sdt_state = GET_DUMP; + } rc = ipr_reset_reload(ioa_cfg, IPR_SHUTDOWN_ABBREV); @@ -4907,7 +4909,7 @@ static int ipr_cancel_op(struct scsi_cmnd * scsi_cmd) struct ipr_ioa_cfg *ioa_cfg; struct ipr_resource_entry *res; struct ipr_cmd_pkt *cmd_pkt; - u32 ioasc; + u32 ioasc, int_reg; int op_found = 0; ENTER; @@ -4920,7 +4922,17 @@ static int ipr_cancel_op(struct scsi_cmnd * scsi_cmd) */ if (ioa_cfg->in_reset_reload || ioa_cfg->ioa_is_dead) return FAILED; - if (!res || !ipr_is_gscsi(res)) + if (!res) + return FAILED; + + /* + * If we are aborting a timed out op, chances are that the timeout was caused + * by a still not detected EEH error. In such cases, reading a register will + * trigger the EEH recovery infrastructure. + */ + int_reg = readl(ioa_cfg->regs.sense_interrupt_reg); + + if (!ipr_is_gscsi(res)) return FAILED; list_for_each_entry(ipr_cmd, &ioa_cfg->pending_q, queue) { -- cgit v1.2.3