* [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store()
@ 2019-08-31 12:49 YueHaibing
2019-09-02 7:50 ` Christoph Hellwig
2019-09-03 8:22 ` [PATCH v2 -next] PCI: Don't use GFP_KERNEL for kstrbdup in resource_alignment_store YueHaibing
0 siblings, 2 replies; 5+ messages in thread
From: YueHaibing @ 2019-08-31 12:49 UTC (permalink / raw)
To: Bjorn Helgaas, Logan Gunthorpe
Cc: YueHaibing, linux-pci, linux-kernel, kernel-janitors
When allocating memory, the GFP_KERNEL cannot be used during the
spin_lock period. It may cause scheduling when holding spin_lock.
Fixes: f13755318675 ("PCI: Move pci_[get|set]_resource_alignment_param() into their callers")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
drivers/pci/pci.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 484e35349565..0b5fc6736f3f 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6148,7 +6148,7 @@ static ssize_t resource_alignment_store(struct bus_type *bus,
spin_lock(&resource_alignment_lock);
kfree(resource_alignment_param);
- resource_alignment_param = kstrndup(buf, count, GFP_KERNEL);
+ resource_alignment_param = kstrndup(buf, count, GFP_ATOMIC);
spin_unlock(&resource_alignment_lock);
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store() 2019-08-31 12:49 [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store() YueHaibing @ 2019-09-02 7:50 ` Christoph Hellwig 2019-09-03 15:51 ` Logan Gunthorpe 2019-09-03 8:22 ` [PATCH v2 -next] PCI: Don't use GFP_KERNEL for kstrbdup in resource_alignment_store YueHaibing 1 sibling, 1 reply; 5+ messages in thread From: Christoph Hellwig @ 2019-09-02 7:50 UTC (permalink / raw) To: YueHaibing Cc: Bjorn Helgaas, Logan Gunthorpe, linux-pci, linux-kernel, kernel-janitors On Sat, Aug 31, 2019 at 12:49:32PM +0000, YueHaibing wrote: > When allocating memory, the GFP_KERNEL cannot be used during the > spin_lock period. It may cause scheduling when holding spin_lock. > > Fixes: f13755318675 ("PCI: Move pci_[get|set]_resource_alignment_param() into their callers") > Signed-off-by: YueHaibing <yuehaibing@huawei.com> > --- > drivers/pci/pci.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 484e35349565..0b5fc6736f3f 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6148,7 +6148,7 @@ static ssize_t resource_alignment_store(struct bus_type *bus, > spin_lock(&resource_alignment_lock); > > kfree(resource_alignment_param); > - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); > + resource_alignment_param = kstrndup(buf, count, GFP_ATOMIC); > > spin_unlock(&resource_alignment_lock); Why not move the allocation outside the lock? Something like this seems much more sensible: diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 484e35349565..fe205829f676 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6145,14 +6145,16 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf) static ssize_t resource_alignment_store(struct bus_type *bus, const char *buf, size_t count) { - spin_lock(&resource_alignment_lock); + char *param = kstrndup(buf, count, GFP_KERNEL); - kfree(resource_alignment_param); - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); + if (!param) + return -ENOMEM; + spin_lock(&resource_alignment_lock); + kfree(resource_alignment_param); + resource_alignment_param = param; spin_unlock(&resource_alignment_lock); - - return resource_alignment_param ? count : -ENOMEM; + return count; } static BUS_ATTR_RW(resource_alignment); ^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store() 2019-09-02 7:50 ` Christoph Hellwig @ 2019-09-03 15:51 ` Logan Gunthorpe 2019-09-05 21:47 ` Bjorn Helgaas 0 siblings, 1 reply; 5+ messages in thread From: Logan Gunthorpe @ 2019-09-03 15:51 UTC (permalink / raw) To: Christoph Hellwig, YueHaibing Cc: Bjorn Helgaas, linux-pci, linux-kernel, kernel-janitors On 2019-09-02 1:50 a.m., Christoph Hellwig wrote: > On Sat, Aug 31, 2019 at 12:49:32PM +0000, YueHaibing wrote: >> When allocating memory, the GFP_KERNEL cannot be used during the >> spin_lock period. It may cause scheduling when holding spin_lock. >> >> Fixes: f13755318675 ("PCI: Move pci_[get|set]_resource_alignment_param() into their callers") >> Signed-off-by: YueHaibing <yuehaibing@huawei.com> >> --- >> drivers/pci/pci.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 484e35349565..0b5fc6736f3f 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -6148,7 +6148,7 @@ static ssize_t resource_alignment_store(struct bus_type *bus, >> spin_lock(&resource_alignment_lock); >> >> kfree(resource_alignment_param); >> - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); >> + resource_alignment_param = kstrndup(buf, count, GFP_ATOMIC); >> >> spin_unlock(&resource_alignment_lock); > > Why not move the allocation outside the lock? Something like this > seems much more sensible: Yes, that seems like a good way to do it. Bjorn, can you squash Christoph's patch or do you want me to resend a new one? Thanks, Logan > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 484e35349565..fe205829f676 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -6145,14 +6145,16 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf) > static ssize_t resource_alignment_store(struct bus_type *bus, > const char *buf, size_t count) > { > - spin_lock(&resource_alignment_lock); > + char *param = kstrndup(buf, count, GFP_KERNEL); > > - kfree(resource_alignment_param); > - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); > + if (!param) > + return -ENOMEM; > > + spin_lock(&resource_alignment_lock); > + kfree(resource_alignment_param); > + resource_alignment_param = param; > spin_unlock(&resource_alignment_lock); > - > - return resource_alignment_param ? count : -ENOMEM; > + return count; > } > > static BUS_ATTR_RW(resource_alignment); > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store() 2019-09-03 15:51 ` Logan Gunthorpe @ 2019-09-05 21:47 ` Bjorn Helgaas 0 siblings, 0 replies; 5+ messages in thread From: Bjorn Helgaas @ 2019-09-05 21:47 UTC (permalink / raw) To: Logan Gunthorpe Cc: Christoph Hellwig, YueHaibing, linux-pci, linux-kernel, kernel-janitors On Tue, Sep 03, 2019 at 09:51:05AM -0600, Logan Gunthorpe wrote: > > > On 2019-09-02 1:50 a.m., Christoph Hellwig wrote: > > On Sat, Aug 31, 2019 at 12:49:32PM +0000, YueHaibing wrote: > >> When allocating memory, the GFP_KERNEL cannot be used during the > >> spin_lock period. It may cause scheduling when holding spin_lock. > >> > >> Fixes: f13755318675 ("PCI: Move pci_[get|set]_resource_alignment_param() into their callers") > >> Signed-off-by: YueHaibing <yuehaibing@huawei.com> > >> --- > >> drivers/pci/pci.c | 2 +- > >> 1 file changed, 1 insertion(+), 1 deletion(-) > >> > >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > >> index 484e35349565..0b5fc6736f3f 100644 > >> --- a/drivers/pci/pci.c > >> +++ b/drivers/pci/pci.c > >> @@ -6148,7 +6148,7 @@ static ssize_t resource_alignment_store(struct bus_type *bus, > >> spin_lock(&resource_alignment_lock); > >> > >> kfree(resource_alignment_param); > >> - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); > >> + resource_alignment_param = kstrndup(buf, count, GFP_ATOMIC); > >> > >> spin_unlock(&resource_alignment_lock); > > > > Why not move the allocation outside the lock? Something like this > > seems much more sensible: > > Yes, that seems like a good way to do it. Bjorn, can you squash > Christoph's patch or do you want me to resend a new one? I folded Christoph's fix into it, thanks! > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index 484e35349565..fe205829f676 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -6145,14 +6145,16 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf) > > static ssize_t resource_alignment_store(struct bus_type *bus, > > const char *buf, size_t count) > > { > > - spin_lock(&resource_alignment_lock); > > + char *param = kstrndup(buf, count, GFP_KERNEL); > > > > - kfree(resource_alignment_param); > > - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); > > + if (!param) > > + return -ENOMEM; > > > > + spin_lock(&resource_alignment_lock); > > + kfree(resource_alignment_param); > > + resource_alignment_param = param; > > spin_unlock(&resource_alignment_lock); > > - > > - return resource_alignment_param ? count : -ENOMEM; > > + return count; > > } > > > > static BUS_ATTR_RW(resource_alignment); > > ^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v2 -next] PCI: Don't use GFP_KERNEL for kstrbdup in resource_alignment_store 2019-08-31 12:49 [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store() YueHaibing 2019-09-02 7:50 ` Christoph Hellwig @ 2019-09-03 8:22 ` YueHaibing 1 sibling, 0 replies; 5+ messages in thread From: YueHaibing @ 2019-09-03 8:22 UTC (permalink / raw) To: bhelgaas, hch; +Cc: linux-pci, linux-kernel, YueHaibing When allocating memory, the GFP_KERNEL cannot be used during the spin_lock period. It may cause scheduling when holding spin_lock. Suggested-by: Christoph Hellwig <hch@infradead.org> Fixes: f13755318675 ("PCI: Move pci_[get|set]_resource_alignment_param() into their callers") Signed-off-by: YueHaibing <yuehaibing@huawei.com> --- v2: move alloc out of spinlock --- drivers/pci/pci.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 484e353..a3d5920 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6145,14 +6145,17 @@ static ssize_t resource_alignment_show(struct bus_type *bus, char *buf) static ssize_t resource_alignment_store(struct bus_type *bus, const char *buf, size_t count) { - spin_lock(&resource_alignment_lock); + char *param = kstrndup(buf, count, GFP_KERNEL); - kfree(resource_alignment_param); - resource_alignment_param = kstrndup(buf, count, GFP_KERNEL); + if (!param) + return -ENOMEM; + spin_lock(&resource_alignment_lock); + kfree(resource_alignment_param); + resource_alignment_param = param; spin_unlock(&resource_alignment_lock); - return resource_alignment_param ? count : -ENOMEM; + return count; } static BUS_ATTR_RW(resource_alignment); -- 2.7.4 ^ permalink raw reply related [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-09-05 21:47 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-08-31 12:49 [PATCH -next] PCI: Use GFP_ATOMIC in resource_alignment_store() YueHaibing 2019-09-02 7:50 ` Christoph Hellwig 2019-09-03 15:51 ` Logan Gunthorpe 2019-09-05 21:47 ` Bjorn Helgaas 2019-09-03 8:22 ` [PATCH v2 -next] PCI: Don't use GFP_KERNEL for kstrbdup in resource_alignment_store YueHaibing
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