From 91ab5d9d02a97264368eb1d72efdba2ec18cc0d4 Mon Sep 17 00:00:00 2001 From: Heiner Kallweit Date: Thu, 13 May 2021 22:56:41 +0200 Subject: [PATCH] PCI/VPD: Make pci_vpd_wait() uninterruptible Reading/writing 4 bytes should be fast enough even on a slow bus, therefore pci_vpd_wait() doesn't have to be interruptible. Making it uninterruptible allows to simplify the code. In addition make VPD writes uninterruptible in general. It's about vital data, and allowing writes to be interruptible may leave the VPD in an inconsistent state. Link: https://lore.kernel.org/r/258bf994-bc2a-2907-9181-2c7a562986d5@gmail.com Signed-off-by: Heiner Kallweit Signed-off-by: Bjorn Helgaas --- drivers/pci/vpd.c | 33 +++++++++------------------------ 1 file changed, 9 insertions(+), 24 deletions(-) diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c index 4f262f8..3d9223f 100644 --- a/drivers/pci/vpd.c +++ b/drivers/pci/vpd.c @@ -24,7 +24,6 @@ struct pci_vpd { unsigned int len; u16 flag; u8 cap; - unsigned int busy:1; unsigned int valid:1; }; @@ -129,22 +128,14 @@ static int pci_vpd_wait(struct pci_dev *dev) u16 status; int ret; - if (!vpd->busy) - return 0; - do { ret = pci_user_read_config_word(dev, vpd->cap + PCI_VPD_ADDR, &status); if (ret < 0) return ret; - if ((status & PCI_VPD_ADDR_F) == vpd->flag) { - vpd->busy = 0; + if ((status & PCI_VPD_ADDR_F) == vpd->flag) return 0; - } - - if (fatal_signal_pending(current)) - return -EINTR; if (time_after(jiffies, timeout)) break; @@ -162,7 +153,7 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count, void *arg) { struct pci_vpd *vpd = dev->vpd; - int ret; + int ret = 0; loff_t end = pos + count; u8 *buf = arg; @@ -188,19 +179,19 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count, if (mutex_lock_killable(&vpd->lock)) return -EINTR; - ret = pci_vpd_wait(dev); - if (ret < 0) - goto out; - while (pos < end) { u32 val; unsigned int i, skip; + if (fatal_signal_pending(current)) { + ret = -EINTR; + break; + } + ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, pos & ~3); if (ret < 0) break; - vpd->busy = 1; vpd->flag = PCI_VPD_ADDR_F; ret = pci_vpd_wait(dev); if (ret < 0) @@ -220,7 +211,7 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count, val >>= 8; } } -out: + mutex_unlock(&vpd->lock); return ret ? ret : count; } @@ -250,10 +241,6 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count, if (mutex_lock_killable(&vpd->lock)) return -EINTR; - ret = pci_vpd_wait(dev); - if (ret < 0) - goto out; - while (pos < end) { u32 val; @@ -270,7 +257,6 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count, if (ret < 0) break; - vpd->busy = 1; vpd->flag = 0; ret = pci_vpd_wait(dev); if (ret < 0) @@ -278,7 +264,7 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count, pos += sizeof(u32); } -out: + mutex_unlock(&vpd->lock); return ret ? ret : count; } @@ -341,7 +327,6 @@ void pci_vpd_init(struct pci_dev *dev) vpd->ops = &pci_vpd_ops; mutex_init(&vpd->lock); vpd->cap = cap; - vpd->busy = 0; vpd->valid = 0; dev->vpd = vpd; } -- 2.7.4