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SubjectRe: [patch] PCI: check the return value of device_create_bin_file() in pci_create_bus()
Check the return value of device_create_bin_file in pci_create_bus and
unwind if necessary. Don't propagate error to caller, as failure to create
these files shouldn't prevent PCI from being initialised. Instead, just
log a warning.

Cc: Sven Wegener <sven.wegener@stealer.net>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Simon Horman <horms@verge.net.au>

---

Tue, 5 Aug 2008 21:14:07 +1000
* Revised the patch to free and NULLify b->legacy_io in
pci_create_legacy_files() on error.

Wed, 06 Aug 2008 10:49:30 +1000
* Don't propagate error to caller, as failure to create these files
shouldn't prevent PCI from being initialised.

Thu, 07 Aug 2008 09:28:56 +1000
* Remove spurious return value.
Amusingly this patch was introducing warnings :-)

Thu, 07 Aug 2008 11:15:32 +1000
* Print a warning if legacy file initialisation fails.

This patch resolves the following warnings:

drivers/pci/probe.c: In function `pci_create_bus':
drivers/pci/probe.c:66: warning: ignoring return value of `device_create_bin_file', declared with attribute warn_unused_result
drivers/pci/probe.c:74: warning: ignoring return value of `device_create_bin_file', declared with attribute warn_unused_result

# ia64-unknown-linux-gnu-gcc --version
ia64-unknown-linux-gnu-gcc (GCC) 3.4.5
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Index: linux-2.6/drivers/pci/probe.c
===================================================================
--- linux-2.6.orig/drivers/pci/probe.c 2008-08-07 09:08:32.000000000 +1000
+++ linux-2.6/drivers/pci/probe.c 2008-08-07 11:21:31.000000000 +1000
@@ -52,27 +52,49 @@ EXPORT_SYMBOL(no_pci_devices);
* Some platforms allow access to legacy I/O port and ISA memory space on
* a per-bus basis. This routine creates the files and ties them into
* their associated read, write and mmap files from pci-sysfs.c
+ *
+ * On error unwind, but don't propogate the error to the caller
+ * as it is ok to set up the PCI bus without these files.
*/
static void pci_create_legacy_files(struct pci_bus *b)
{
+ int error;
+
b->legacy_io = kzalloc(sizeof(struct bin_attribute) * 2,
GFP_ATOMIC);
- if (b->legacy_io) {
- b->legacy_io->attr.name = "legacy_io";
- b->legacy_io->size = 0xffff;
- b->legacy_io->attr.mode = S_IRUSR | S_IWUSR;
- b->legacy_io->read = pci_read_legacy_io;
- b->legacy_io->write = pci_write_legacy_io;
- device_create_bin_file(&b->dev, b->legacy_io);
-
- /* Allocated above after the legacy_io struct */
- b->legacy_mem = b->legacy_io + 1;
- b->legacy_mem->attr.name = "legacy_mem";
- b->legacy_mem->size = 1024*1024;
- b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;
- b->legacy_mem->mmap = pci_mmap_legacy_mem;
- device_create_bin_file(&b->dev, b->legacy_mem);
- }
+ if (!b->legacy_io)
+ goto kzalloc_err;
+
+ b->legacy_io->attr.name = "legacy_io";
+ b->legacy_io->size = 0xffff;
+ b->legacy_io->attr.mode = S_IRUSR | S_IWUSR;
+ b->legacy_io->read = pci_read_legacy_io;
+ b->legacy_io->write = pci_write_legacy_io;
+ error = device_create_bin_file(&b->dev, b->legacy_io);
+ if (error)
+ goto legacy_io_err;
+
+ /* Allocated above after the legacy_io struct */
+ b->legacy_mem = b->legacy_io + 1;
+ b->legacy_mem->attr.name = "legacy_mem";
+ b->legacy_mem->size = 1024*1024;
+ b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;
+ b->legacy_mem->mmap = pci_mmap_legacy_mem;
+ error = device_create_bin_file(&b->dev, b->legacy_mem);
+ if (error)
+ goto legacy_mem_err;
+
+ return;
+
+legacy_mem_err:
+ device_remove_bin_file(&b->dev, b->legacy_io);
+legacy_io_err:
+ kfree(b->legacy_io);
+ b->legacy_io = NULL;
+kzalloc_err:
+ printk(KERN_WARNING "pci: warning: could not create legacy I/O port "
+ "and ISA memory resources to sysfs\n");
+ return;
}

void pci_remove_legacy_files(struct pci_bus *b)

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