diff options
| author | Niklas Schnelle <schnelle@linux.ibm.com> | 2025-05-22 14:13:15 +0200 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2025-05-22 16:12:53 +0200 |
| commit | 774a1fa880bc949d88b5ddec9494a13be733dfa8 (patch) | |
| tree | a4042a0d020327d5dc0a64fd1d314dc779bafc7d | |
| parent | 4b1815a52d7eb03b3e0e6742c6728bc16a4b2d1d (diff) | |
s390/pci: Serialize device addition and removal
Prior changes ensured that when zpci_release_device() is called and it
removed the zdev from the zpci_list this instance can not be found via
the zpci_list anymore even while allowing re-add of reserved devices.
This only accounts for the overall lifetime and zpci_list addition and
removal, it does not yet prevent concurrent add of a new instance for
the same underlying device. Such concurrent add would subsequently cause
issues such as attempted re-use of the same IOMMU sysfs directory and is
generally undesired.
Introduce a new zpci_add_remove_lock mutex to serialize adding a new
device with removal. Together this ensures that if a struct zpci_dev is
not found in the zpci_list it was either already removed and torn down,
or its removal and tear down is in progress with the
zpci_add_remove_lock held.
Cc: stable@vger.kernel.org
Fixes: a46044a92add ("s390/pci: fix zpci_zdev_put() on reserve")
Reviewed-by: Gerd Bayer <gbayer@linux.ibm.com>
Tested-by: Gerd Bayer <gbayer@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
| -rw-r--r-- | arch/s390/pci/pci.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c index 4602abd0c6f1..cd6676c2d602 100644 --- a/arch/s390/pci/pci.c +++ b/arch/s390/pci/pci.c @@ -45,6 +45,7 @@ /* list of all detected zpci devices */ static LIST_HEAD(zpci_list); static DEFINE_SPINLOCK(zpci_list_lock); +static DEFINE_MUTEX(zpci_add_remove_lock); static DECLARE_BITMAP(zpci_domain, ZPCI_DOMAIN_BITMAP_SIZE); static DEFINE_SPINLOCK(zpci_domain_lock); @@ -74,7 +75,9 @@ void zpci_zdev_put(struct zpci_dev *zdev) { if (!zdev) return; + mutex_lock(&zpci_add_remove_lock); kref_put_lock(&zdev->kref, zpci_release_device, &zpci_list_lock); + mutex_unlock(&zpci_add_remove_lock); } struct zpci_dev *get_zdev_by_fid(u32 fid) @@ -844,6 +847,7 @@ int zpci_add_device(struct zpci_dev *zdev) { int rc; + mutex_lock(&zpci_add_remove_lock); zpci_dbg(1, "add fid:%x, fh:%x, c:%d\n", zdev->fid, zdev->fh, zdev->state); rc = zpci_init_iommu(zdev); if (rc) @@ -857,12 +861,14 @@ int zpci_add_device(struct zpci_dev *zdev) spin_lock(&zpci_list_lock); list_add_tail(&zdev->entry, &zpci_list); spin_unlock(&zpci_list_lock); + mutex_unlock(&zpci_add_remove_lock); return 0; error_destroy_iommu: zpci_destroy_iommu(zdev); error: zpci_dbg(0, "add fid:%x, rc:%d\n", zdev->fid, rc); + mutex_unlock(&zpci_add_remove_lock); return rc; } @@ -953,6 +959,7 @@ void zpci_release_device(struct kref *kref) { struct zpci_dev *zdev = container_of(kref, struct zpci_dev, kref); + lockdep_assert_held(&zpci_add_remove_lock); WARN_ON(zdev->state != ZPCI_FN_STATE_RESERVED); /* * We already hold zpci_list_lock thanks to kref_put_lock(). |