Messages in this thread Patch in this message | | | Date | Thu, 28 Apr 2016 17:11:56 +0200 | From | Vyacheslav Yurkov <> | Subject | Re: [PATCH] drivers/base: wrong return value of dmam_declare_coherent_memory |
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On 28.04.2016 16:31, Andrey Gursky wrote: > Vyacheslav, > > thanks for your patch. > > For now it introduces a new bug. > > Vyacheslav Yurkov <uvv.mail <at> gmail.com> writes: > >> >> Hi guys, >> I found an issue in managed version of dma_declare_coherent_memory, >> i.e. in dmam_declare_coherent_memory. It looks like the return value >> of dma_declare_coherent_memory is zero in case of error and a >> requested flag on success, > > You should take this into account and not ignore the value of rc at all > by using flags instead, which is not being altered by > dma_declare_coherent_memory() making the latter appear to succeed > always. > >
Hi Andrey, Thanks for spotting this. My intention was to compare rc of course, not the flags. While thinking it over I came up with improved version, which is inlined below. --- Yours sincerely, Vyacheslav V. Yurkov
P.S.: I'm not subscribed to the maillist, so please include me in CC when responding to this Email.
--- --- linux-4.5.2/drivers/base/dma-mapping.c.orig 2016-04-20 08:46:35.000000000 +0200 +++ linux-4.5.2/drivers/base/dma-mapping.c 2016-04-28 16:55:13.211945276 +0200 @@ -198,10 +198,14 @@ int dmam_declare_coherent_memory(struct rc = dma_declare_coherent_memory(dev, phys_addr, device_addr, size, flags); - if (rc == 0) + + if ((rc & (DMA_MEMORY_MAP | DMA_MEMORY_IO)) != 0) { devres_add(dev, res); - else + rc = 0; + } else { devres_free(res); + rc = -ENOMEM; + } return rc; } Signed-off-by: Vyacheslav Yurkov <uvv.mail@gmail.com>
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