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Code Issues Releases Wiki Activity

PCI/VPD: Make pci_vpd_wait() uninterruptible

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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 <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Heiner Kallweit 2021-05-13 22:56:41 +02:00 committed by Bjorn Helgaas
parent 1285762c07
commit 91ab5d9d02
1 changed files with 9 additions and 24 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

33
drivers/pci/vpd.c
View file

@ -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;
}