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c17b0aadb7
I have one regression fix for a minor build problem after the architecture removal series, plus a rework of the barriers in the readl/writel functions, thanks to work by Sinan Kaya: This started from a discussion on the linuxpcc and rdma mailing lists [1]. To summarize, we decided that architectures are responsible to serialize readl() and writel() accesses on a device MMIO space relative to DMA performed by that device. This series provides a pessimistic implementation of that behavior for asm-generic/io.h, which is in turn used by a number of architectures (h8300, microblaze, nios2, openrisc, s390, sparc, um, unicore32, and xtensa). Some of those presumably need no extra barriers, or something weaker than rmb()/wmb(), and they are advised to override the new default for better performance. For inb()/outb(), the same barriers are used, but architectures might want to add another barrier to outb() here if that can guarantee non-posted behavior (some architectures can, others cannot do that). The readl_relaxed()/writel_relaxed() family of functions retains the existing behavior with no extra barriers. [1]: https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-March/170481.html -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAABAgAGBQJazitHAAoJEGCrR//JCVInd0wP/iMzr1HWDgMjeeuxekFjwWDg 9fL+BFt1afeYb4wniqJcF7ymLow/H5Fbhj4dwM1p34De+CZ3+3JGNyK8qzoeKPjR I2U5QqjWCHWDqpWRGWxO28dbs5/1EoW1zgctTNMUPHiamnomz9XIn0xaVKpu4HZ3 OtaeJm8seKTSj1+A2fye9sDpqMUJuVcnZAWJgqMJ8T98uMBOiJYWHftnFEJpSlwG SJSt4AYsJnE+3BFawX1g3VWrHn9WN1uwVasJ1INFkLYNuLMYaK7RYjoBWNwHW+RQ luq4xZE+HZehyZptilfs05x2IlhGSOVN5m0nVM2if9aXoEoO1UdaySbwO6Ukq085 VyfCzY+k4l0v44o4JqaSyAFLEae0809E6cQcGg3cjdstQv1Q3cgAJ96myP0x+QTw b0xJGoo46eOfqpK4njARyjTSceYPgzkB5Dqngg9rCuh+EogotWpRRDB6zoeGGRK8 oOzMp0qLsAZFcYvjft5h0Cp6X51qfyJpBkJkvnASmF4yJPZlpCRGux+HM3jFb9bV zbH+KPqTa47OmOK8MNIaFHMR1yMgZU6B2oEwFDEaG0M+6FC5irMSkgcDwIIMJXlJ wLp7+4WhwFzFDe1mp/tKM5V4h9D6vQtSUjgOJffhxRXqCMkxc7eABmYBBkjMCsca ibKXyZN16d1kRU9j7upb =oBQh -----END PGP SIGNATURE----- Merge tag 'asm-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic Pull asm-generic fixes from Arnd Bergmann: "I have one regression fix for a minor build problem after the architecture removal series, plus a rework of the barriers in the readl/writel functions, thanks to work by Sinan Kaya: This started from a discussion on the linuxpcc and rdma mailing lists[1]. To summarize, we decided that architectures are responsible to serialize readl() and writel() accesses on a device MMIO space relative to DMA performed by that device. This series provides a pessimistic implementation of that behavior for asm-generic/io.h, which is in turn used by a number of architectures (h8300, microblaze, nios2, openrisc, s390, sparc, um, unicore32, and xtensa). Some of those presumably need no extra barriers, or something weaker than rmb()/wmb(), and they are advised to override the new default for better performance. For inb()/outb(), the same barriers are used, but architectures might want to add another barrier to outb() here if that can guarantee non-posted behavior (some architectures can, others cannot do that). The readl_relaxed()/writel_relaxed() family of functions retains the existing behavior with no extra barriers" [1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2018-March/170481.html * tag 'asm-generic' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: io: change writeX_relaxed() to remove barriers io: change readX_relaxed() to remove barriers dts: remove cris & metag dts hard link file io: change inX() to have their own IO barrier overrides io: change outX() to have their own IO barrier overrides io: define stronger ordering for the default writeX() implementation io: define stronger ordering for the default readX() implementation io: define several IO & PIO barrier types for the asm-generic version