* [PATCH] staging: netlogic: Remove unnecessary error print @ 2019-03-21 9:57 Himadri Pandya 2019-03-21 10:08 ` [Outreachy kernel] " Julia Lawall 0 siblings, 1 reply; 4+ messages in thread From: Himadri Pandya @ 2019-03-21 9:57 UTC (permalink / raw) To: gregkh; +Cc: outreachy-kernel, Himadri Pandya Kmalloc normally produces a backtrace when there is not enough memory. So it is unnecessary to print an error message that provides only this information. Hence, remove pr_error() from memory allocation check. Issue found using Coccinelle. Signed-off-by: Himadri Pandya <himadri18.07@gmail.com> --- drivers/staging/netlogic/xlr_net.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/staging/netlogic/xlr_net.c b/drivers/staging/netlogic/xlr_net.c index 8554fcf4321b..afba1248e100 100644 --- a/drivers/staging/netlogic/xlr_net.c +++ b/drivers/staging/netlogic/xlr_net.c @@ -389,10 +389,8 @@ static void *xlr_config_spill(struct xlr_net_priv *priv, int reg_start_0, base = priv->base_addr; spill_size = size; spill = kmalloc(spill_size + SMP_CACHE_BYTES, GFP_ATOMIC); - if (!spill) { - pr_err("Unable to allocate memory for spill area!\n"); + if (!spill) return ZERO_SIZE_PTR; - } spill = PTR_ALIGN(spill, SMP_CACHE_BYTES); phys_addr = virt_to_phys(spill); -- 2.17.1 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [Outreachy kernel] [PATCH] staging: netlogic: Remove unnecessary error print 2019-03-21 9:57 [PATCH] staging: netlogic: Remove unnecessary error print Himadri Pandya @ 2019-03-21 10:08 ` Julia Lawall 2019-03-21 10:40 ` Himadri Pandya 0 siblings, 1 reply; 4+ messages in thread From: Julia Lawall @ 2019-03-21 10:08 UTC (permalink / raw) To: Himadri Pandya; +Cc: gregkh, outreachy-kernel On Thu, 21 Mar 2019, Himadri Pandya wrote: > Kmalloc normally produces a backtrace when there is not enough memory. > So it is unnecessary to print an error message that provides only this > information. Hence, remove pr_error() from memory allocation check. > Issue found using Coccinelle. > > Signed-off-by: Himadri Pandya <himadri18.07@gmail.com> > --- > drivers/staging/netlogic/xlr_net.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/staging/netlogic/xlr_net.c b/drivers/staging/netlogic/xlr_net.c > index 8554fcf4321b..afba1248e100 100644 > --- a/drivers/staging/netlogic/xlr_net.c > +++ b/drivers/staging/netlogic/xlr_net.c > @@ -389,10 +389,8 @@ static void *xlr_config_spill(struct xlr_net_priv *priv, int reg_start_0, > base = priv->base_addr; > spill_size = size; > spill = kmalloc(spill_size + SMP_CACHE_BYTES, GFP_ATOMIC); > - if (!spill) { > - pr_err("Unable to allocate memory for spill area!\n"); > + if (!spill) > return ZERO_SIZE_PTR; This seems to be the only driver that uses ZERO_SIZE_PTR as the result for kmalloc. It could be worth looking into what happens to this value afterwards. julia > - } > > spill = PTR_ALIGN(spill, SMP_CACHE_BYTES); > phys_addr = virt_to_phys(spill); > -- > 2.17.1 > > -- > You received this message because you are subscribed to the Google Groups "outreachy-kernel" group. > To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com. > To post to this group, send email to outreachy-kernel@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/20190321095717.24155-1-himadri18.07%40gmail.com. > For more options, visit https://groups.google.com/d/optout. > ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Outreachy kernel] [PATCH] staging: netlogic: Remove unnecessary error print 2019-03-21 10:08 ` [Outreachy kernel] " Julia Lawall @ 2019-03-21 10:40 ` Himadri Pandya 2019-03-21 10:42 ` Julia Lawall 0 siblings, 1 reply; 4+ messages in thread From: Himadri Pandya @ 2019-03-21 10:40 UTC (permalink / raw) To: Julia Lawall; +Cc: Greg KH, outreachy-kernel [-- Attachment #1: Type: text/plain, Size: 2459 bytes --] On Thu, Mar 21, 2019 at 3:38 PM Julia Lawall <julia.lawall@lip6.fr> wrote: > > > On Thu, 21 Mar 2019, Himadri Pandya wrote: > > > Kmalloc normally produces a backtrace when there is not enough memory. > > So it is unnecessary to print an error message that provides only this > > information. Hence, remove pr_error() from memory allocation check. > > Issue found using Coccinelle. > > > > Signed-off-by: Himadri Pandya <himadri18.07@gmail.com> > > --- > > drivers/staging/netlogic/xlr_net.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/staging/netlogic/xlr_net.c > b/drivers/staging/netlogic/xlr_net.c > > index 8554fcf4321b..afba1248e100 100644 > > --- a/drivers/staging/netlogic/xlr_net.c > > +++ b/drivers/staging/netlogic/xlr_net.c > > @@ -389,10 +389,8 @@ static void *xlr_config_spill(struct xlr_net_priv > *priv, int reg_start_0, > > base = priv->base_addr; > > spill_size = size; > > spill = kmalloc(spill_size + SMP_CACHE_BYTES, GFP_ATOMIC); > > - if (!spill) { > > - pr_err("Unable to allocate memory for spill area!\n"); > > + if (!spill) > > return ZERO_SIZE_PTR; > > This seems to be the only driver that uses ZERO_SIZE_PTR as the result for > kmalloc. It could be worth looking into what happens to this value > afterwards. > > julia > This is interesting. Later the pointer *spill* is aligned with *SMP_CACHE_BYTE**S (which is defined using L1_CACHE_BYTES). * As per my understanding, *xlr_config_spill() *returns ZERO_SIZE_PTR if *kmalloc()* cannot allocate sufficient memory(equivalent to *spill_size*) as the return value is being used to configure network accelerator's communication interface. Please correct me if I am mistaken. Thank you. - Himadri > > > - } > > > > spill = PTR_ALIGN(spill, SMP_CACHE_BYTES); > > phys_addr = virt_to_phys(spill); > > -- > > 2.17.1 > > > > -- > > You received this message because you are subscribed to the Google > Groups "outreachy-kernel" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to outreachy-kernel+unsubscribe@googlegroups.com. > > To post to this group, send email to outreachy-kernel@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/outreachy-kernel/20190321095717.24155-1-himadri18.07%40gmail.com > . > > For more options, visit https://groups.google.com/d/optout. > > > [-- Attachment #2: Type: text/html, Size: 3765 bytes --] ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Outreachy kernel] [PATCH] staging: netlogic: Remove unnecessary error print 2019-03-21 10:40 ` Himadri Pandya @ 2019-03-21 10:42 ` Julia Lawall 0 siblings, 0 replies; 4+ messages in thread From: Julia Lawall @ 2019-03-21 10:42 UTC (permalink / raw) To: Himadri Pandya; +Cc: Greg KH, outreachy-kernel [-- Attachment #1: Type: text/plain, Size: 3664 bytes --] On Thu, 21 Mar 2019, Himadri Pandya wrote: > > > On Thu, Mar 21, 2019 at 3:38 PM Julia Lawall <julia.lawall@lip6.fr> wrote: > > > On Thu, 21 Mar 2019, Himadri Pandya wrote: > > > Kmalloc normally produces a backtrace when there is not enough memory. > > So it is unnecessary to print an error message that provides only this > > information. Hence, remove pr_error() from memory allocation check. > > Issue found using Coccinelle. > > > > Signed-off-by: Himadri Pandya <himadri18.07@gmail.com> > > --- > >ￜ drivers/staging/netlogic/xlr_net.c | 4 +--- > >ￜ 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/drivers/staging/netlogic/xlr_net.c b/drivers/staging/netlogic/xlr_net.c > > index 8554fcf4321b..afba1248e100 100644 > > --- a/drivers/staging/netlogic/xlr_net.c > > +++ b/drivers/staging/netlogic/xlr_net.c > > @@ -389,10 +389,8 @@ static void *xlr_config_spill(struct xlr_net_priv *priv, int reg_start_0, > >ￜ ￜ ￜ ￜbase = priv->base_addr; > >ￜ ￜ ￜ ￜspill_size = size; > >ￜ ￜ ￜ ￜspill = kmalloc(spill_size + SMP_CACHE_BYTES, GFP_ATOMIC); > > -ￜ ￜ ￜif (!spill) { > > -ￜ ￜ ￜ ￜ ￜ ￜ ￜpr_err("Unable to allocate memory for spill area!\n"); > > +ￜ ￜ ￜif (!spill) > >ￜ ￜ ￜ ￜ ￜ ￜ ￜ ￜreturn ZERO_SIZE_PTR; > > This seems to be the only driver that uses ZERO_SIZE_PTR as the result for > kmalloc.ￜ It could be worth looking into what happens to this value > afterwards. > > julia > > > This is interesting. Later the pointer spillￜis aligned withￜSMP_CACHE_BYTES (which is defined using L1_CACHE_BYTES).ￜￜAs per my understanding,ￜxlr_config_spill() returns ZERO_SIZE_PTR if kmalloc()ￜcannot allocate sufficient > memory(equivalent to spill_size) as the return value is being used to configure network accelerator's communication interface. The questin is who is checking the return value and whether it is checked in the right manner. I looked quickly at the cal site, and it seemed that the result as stored in a structure field with no checking, But perhaps some checking is done afterwards. julia > > Please correct me if I am mistaken. > > Thank you. > > - Himadri > ￜ > > > -ￜ ￜ ￜ} > > > >ￜ ￜ ￜ ￜspill = PTR_ALIGN(spill, SMP_CACHE_BYTES); > >ￜ ￜ ￜ ￜphys_addr = virt_to_phys(spill); > > -- > > 2.17.1 > > > > -- > > You received this message because you are subscribed to the Google Groups "outreachy-kernel" group. > > To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com. > > To post to this group, send email to outreachy-kernel@googlegroups.com. > > To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/20190321095717.24155-1-himadri18.07%40gmail.com. > > For more options, visit https://groups.google.com/d/optout. > > > > -- > You received this message because you are subscribed to the Google Groups "outreachy-kernel" group. > To unsubscribe from this group and stop receiving emails from it, send an email to outreachy-kernel+unsubscribe@googlegroups.com. > To post to this group, send email to outreachy-kernel@googlegroups.com. > To view this discussion on the web visit https://groups.google.com/d/msgid/outreachy-kernel/CAPnhUpaXwEBMFa_ukU9uauFuEaUojMju_kG%2BWHnJ9SQcAXrSpA%40mail.gmail.com. > For more options, visit https://groups.google.com/d/optout. > > ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-03-21 10:43 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2019-03-21 9:57 [PATCH] staging: netlogic: Remove unnecessary error print Himadri Pandya 2019-03-21 10:08 ` [Outreachy kernel] " Julia Lawall 2019-03-21 10:40 ` Himadri Pandya 2019-03-21 10:42 ` Julia Lawall
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