PCI/VPD: Use pci_read_vpd_any() in pci_vpd_size()

Use new function pci_read_vpd_any() to simplify the code.

[bhelgaas: squash in fix for stack overflow reported & tested by
Qian [1] and Kunihiko [2]:
[1] https://lore.kernel.org/netdev/e89087c5-c495-c5ca-feb1-54cf3a8775c5@quicinc.com/
[2] https://lore.kernel.org/r/2f7e3770-ab47-42b5-719c-f7c661c07d28@socionext.com
Link: https://lore.kernel.org/r/6211be8a-5d10-8f3a-6d33-af695dc35caf@gmail.com
Reported-by: Qian Cai <quic_qiancai@quicinc.com>
Tested-by: Qian Cai <quic_qiancai@quicinc.com>
Reported-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Tested-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
]

Link: https://lore.kernel.org/r/049fa71c-c7af-9c69-51c0-05c1bc2bf660@gmail.com
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/pci/vpd.c b/drivers/pci/vpd.c
index 0a80471..a4fc4d0 100644 (file)
--- a/drivers/pci/vpd.c
+++ b/drivers/pci/vpd.c
@@ -57,10 +57,7 @@ static size_t pci_vpd_size(struct pci_dev *dev)
        size_t off = 0, size;
        unsigned char tag, header[1+2]; /* 1 byte tag, 2 bytes length */
 
-       /* Otherwise the following reads would fail. */
-       dev->vpd.len = PCI_VPD_MAX_SIZE;
-
-       while (pci_read_vpd(dev, off, 1, header) == 1) {
+       while (pci_read_vpd_any(dev, off, 1, header) == 1) {
                size = 0;
 
                if (off == 0 && (header[0] == 0x00 || header[0] == 0xff))
@@ -68,7 +65,7 @@ static size_t pci_vpd_size(struct pci_dev *dev)
 
                if (header[0] & PCI_VPD_LRDT) {
                        /* Large Resource Data Type Tag */
-                       if (pci_read_vpd(dev, off + 1, 2, &header[1]) != 2) {
+                       if (pci_read_vpd_any(dev, off + 1, 2, &header[1]) != 2) {
                                pci_warn(dev, "failed VPD read at offset %zu\n",
                                         off + 1);
                                return off ?: PCI_VPD_SZ_INVALID;
@@ -99,14 +96,14 @@ error:
        return off ?: PCI_VPD_SZ_INVALID;
 }
 
-static bool pci_vpd_available(struct pci_dev *dev)
+static bool pci_vpd_available(struct pci_dev *dev, bool check_size)
 {
        struct pci_vpd *vpd = &dev->vpd;
 
        if (!vpd->cap)
                return false;
 
-       if (vpd->len == 0) {
+       if (vpd->len == 0 && check_size) {
                vpd->len = pci_vpd_size(dev);
                if (vpd->len == PCI_VPD_SZ_INVALID) {
                        vpd->cap = 0;
@@ -159,17 +156,19 @@ static ssize_t pci_vpd_read(struct pci_dev *dev, loff_t pos, size_t count,
                            void *arg, bool check_size)
 {
        struct pci_vpd *vpd = &dev->vpd;
-       unsigned int max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+       unsigned int max_len;
        int ret = 0;
        loff_t end = pos + count;
        u8 *buf = arg;
 
-       if (!pci_vpd_available(dev))
+       if (!pci_vpd_available(dev, check_size))
                return -ENODEV;
 
        if (pos < 0)
                return -EINVAL;
 
+       max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+
        if (pos >= max_len)
                return 0;
 
@@ -221,17 +220,19 @@ static ssize_t pci_vpd_write(struct pci_dev *dev, loff_t pos, size_t count,
                             const void *arg, bool check_size)
 {
        struct pci_vpd *vpd = &dev->vpd;
-       unsigned int max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+       unsigned int max_len;
        const u8 *buf = arg;
        loff_t end = pos + count;
        int ret = 0;
 
-       if (!pci_vpd_available(dev))
+       if (!pci_vpd_available(dev, check_size))
                return -ENODEV;
 
        if (pos < 0 || (pos & 3) || (count & 3))
                return -EINVAL;
 
+       max_len = check_size ? vpd->len : PCI_VPD_MAX_SIZE;
+
        if (end > max_len)
                return -EINVAL;
 
@@ -315,7 +316,7 @@ void *pci_vpd_alloc(struct pci_dev *dev, unsigned int *size)
        void *buf;
        int cnt;
 
-       if (!pci_vpd_available(dev))
+       if (!pci_vpd_available(dev, true))
                return ERR_PTR(-ENODEV);
 
        len = dev->vpd.len;