When 'pci=resource_alignment=' is specified on the command line, there is no trailing new line. Then, when it's read through the corresponding sysfs attribute, there will be no newline and a cat command will not show correctly in a shell. If the parameter is set through sysfs a new line will be stored and it will 'cat' correctly.
To solve this, append a new line character in the show function if one does not already exist. Signed-off-by: Logan Gunthorpe <[email protected]> Cc: Bjorn Helgaas <[email protected]> --- drivers/pci/pci.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 5e00371149b1..4748362d6a49 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6117,6 +6117,16 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf) count = snprintf(buf, PAGE_SIZE, "%s", 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; } -- 2.20.1
