@@ -6439,34 +6439,37 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf)
spin_lock(&resource_alignment_lock);
if (resource_alignment_param)
- count = sysfs_emit(buf, "%s", resource_alignment_param);
+ count = sysfs_emit(buf, "%s\n", resource_alignment_param);
spin_unlock(&resource_alignment_lock);
- /*
- * When set by the command line, resource_alignment_param will not
- * have a trailing line feed, which is ugly. So conditionally add
- * it here.
- */
- if (count >= 2 && buf[count - 2] != '\n' && count < PAGE_SIZE - 1) {
- buf[count - 1] = '\n';
- buf[count++] = 0;
- }
-
return count;
}
static ssize_t resource_alignment_store(struct bus_type *bus,
const char *buf, size_t count)
{
- char *param = kstrndup(buf, count, GFP_KERNEL);
+ char *param, *old, *end;
+ param = kstrndup(buf, count, GFP_KERNEL);
if (!param)
return -ENOMEM;
+ end = strchr(param, '\n');
+ if (end)
+ *end = '\0';
+
spin_lock(&resource_alignment_lock);
- kfree(resource_alignment_param);
- resource_alignment_param = param;
+ old = resource_alignment_param;
+ if (strlen(param)) {
+ resource_alignment_param = param;
+ } else {
+ kfree(resource_alignment_param);
+ resource_alignment_param = NULL;
+ }
spin_unlock(&resource_alignment_lock);
+
+ kfree(old);
+
return count;
}
The value of the "resource_alignment" can be specified using a kernel command-line argument (using the "pci=resource_alignment=") or through the corresponding sysfs object under the /sys/bus/pci path. Currently, when the value is set via the kernel command-line argument, and then subsequently accessed through sysfs object, the value read back will not be correct, as per: # grep -oE 'pci=resource_alignment.+' /proc/cmdline pci=resource_alignment=20@00:1f.2 # cat /sys/bus/pci/resource_alignment 20@00:1f. This is also true when the value is set through the sysfs object, but the trailing newline has not been included, as per: # echo -n 20@00:1f.2 > /sys/bus/pci/resource_alignment # cat /sys/bus/pci/resource_alignment 20@00:1f. When the value set through the sysfs object includes the trailing newline, then reading it back will work as intended, as per: # echo 20@00:1f.2 > /sys/bus/pci/resource_alignment # cat /sys/bus/pci/resource_alignment 20@00:1f.2 To fix this inconsistency, append a trailing newline in the show() function and strip the trailing line in the store() function if one is present. Also, allow for the value previously set using either a command-line argument or through the sysfs object to be cleared at run-time. Fixes: e499081da1a2 ("PCI: Force trailing new line to resource_alignment_param in sysfs") Signed-off-by: Krzysztof Wilczyński <kw@linux.com> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> --- Changes in v2: None. Changes in v3: Added Logan Gunthorpe's "Reviewed-by". Changes in v4: None. drivers/pci/pci.c | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-)