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author | Niklas Schnelle <schnelle@linux.ibm.com> | 2021-02-12 10:16:46 +0100 |
---|---|---|
committer | Heiko Carstens <hca@linux.ibm.com> | 2021-04-12 12:46:42 +0200 |
commit | 0350276168942a9fb7540c03995229e3502976a2 (patch) | |
tree | 1ab6d861e4030555addf6113a09eb99001ed4cfc /arch/s390/pci/pci_bus.c | |
parent | a50297cf8235b062bcdeaa8b1dad58e69d3e1b43 (diff) | |
download | linux-0350276168942a9fb7540c03995229e3502976a2.tar.bz2 |
s390/pci: use mutex not spinlock for zbus list
In a later change we will first collect all PCI functions from the CLP
List PCI functions call, then register them to/creating the relevant
zbus. Then only after we've created our virtual bus structure will we
scan all zbusses iterating over the zbus list. Since scanning is
relatively slow a spinlock is a bad fit for protecting the
loop over the devices on the zbus. Furthermore doing the probing on the
bus we need to use pci_lock_rescan_remove() as devices are added to
the PCI subsystem and that is a mutex which can't be locked nested
inside a spinlock section. Note that the contention of this lock should
be very low either way as zbusses are only added/removed concurrently on
hotplug events.
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch/s390/pci/pci_bus.c')
-rw-r--r-- | arch/s390/pci/pci_bus.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c index d200e7559725..9bc869afe011 100644 --- a/arch/s390/pci/pci_bus.c +++ b/arch/s390/pci/pci_bus.c @@ -27,7 +27,7 @@ #include "pci_iov.h" static LIST_HEAD(zbus_list); -static DEFINE_SPINLOCK(zbus_list_lock); +static DEFINE_MUTEX(zbus_list_lock); static int zpci_nb_devices; /* zpci_bus_prepare_device - Prepare a zPCI function for scanning @@ -214,9 +214,9 @@ static void zpci_bus_release(struct kref *kref) pci_unlock_rescan_remove(); } - spin_lock(&zbus_list_lock); + mutex_lock(&zbus_list_lock); list_del(&zbus->bus_next); - spin_unlock(&zbus_list_lock); + mutex_unlock(&zbus_list_lock); kfree(zbus); } @@ -229,7 +229,7 @@ static struct zpci_bus *zpci_bus_get(int pchid) { struct zpci_bus *zbus; - spin_lock(&zbus_list_lock); + mutex_lock(&zbus_list_lock); list_for_each_entry(zbus, &zbus_list, bus_next) { if (pchid == zbus->pchid) { kref_get(&zbus->kref); @@ -238,7 +238,7 @@ static struct zpci_bus *zpci_bus_get(int pchid) } zbus = NULL; out_unlock: - spin_unlock(&zbus_list_lock); + mutex_unlock(&zbus_list_lock); return zbus; } @@ -252,9 +252,9 @@ static struct zpci_bus *zpci_bus_alloc(int pchid) zbus->pchid = pchid; INIT_LIST_HEAD(&zbus->bus_next); - spin_lock(&zbus_list_lock); + mutex_lock(&zbus_list_lock); list_add_tail(&zbus->bus_next, &zbus_list); - spin_unlock(&zbus_list_lock); + mutex_unlock(&zbus_list_lock); kref_init(&zbus->kref); INIT_LIST_HEAD(&zbus->resources); |