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Wysocki" , Magnus Karlsson , nex.sw.ncis.osdt.itp.upstreaming@intel.com, bpf@vger.kernel.org, netdev@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org Content-Language: en-US From: Marek Szyprowski In-Reply-To: <20240509144616.938519-1-aleksander.lobakin@intel.com> Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrPKsWRmVeSWpSXmKPExsWy7djPc7opr23SDB5vtbG4+Hkhq8XnI8fZ LJ4ee8RusXL1USaLX18sLDpnb2C3uLCtj9Xi8q45bBYrDp1gtzi2QMxixu2lzBZzv0xltjj4 4QmrReOR92wWLXdMHfg9nhycx+SxZt4aRo8Fm0o9Fu95yeSxaVUnm8eLzTMZPXbfbGDz+LxJ LoAjissmJTUnsyy1SN8ugStj1fbrzAXrdCpWbXjM2sB4VbmLkZNDQsBE4sbX8yxdjFwcQgIr GCUez5rDBuF8YZTYsncrK0iVkMBnRol1fR4wHSemn4XqWM4osWLvHlYI5yOjxO4JN9m7GDk4 eAXsJL7vAmtgEVCR2LXjCyOIzSsgKHFy5hMWEFtUQF7i/q0Z7CC2sECAxORf98CWiQiESTw6 2gNWzyywn1ni/XMtCFtc4taT+UwgNpuAoUTX2y42EJtTwFliTutKJogaeYntb+cwQxy6nlNi +m8WCNtFYtKz3UwQtrDEq+Nb2CFsGYn/O0FmcgHZ7YwSC37fh3ImMEo0PL/FCFFlLXHn3C82 kMeYBTQl1u/Shwg7Svy4dIMJJCwhwCdx460gxA18EpO2TWeGCPNKdLQJQVSrScw6vg5u7cEL l5gnMCrNQgqVWUi+nIXkm1kIexcwsqxiFE8tLc5NTy02zkst1ytOzC0uzUvXS87P3cQITHOn /x3/uoNxxauPeocYmTgYDzFKcDArifBW1VinCfGmJFZWpRblxxeV5qQWH2KU5mBREudVTZFP FRJITyxJzU5NLUgtgskycXBKNTDpzjL8s9wzN3ZtaHJTui+Pqcfsc/Gd8/Zvf3RPMpZDu+Fx waKLi4w/x8pmieYuXJV85aU5n4Of8BnFO590VbnFUtUu1TkFaAucPHbgoLKsi8yR08VCHTt9 N13SbVXezBERVB2eXdZ1sVxS5r+Kf+fq+wnyXpMKHMtPXmk0cGmNM2t1f/CqZdV1o0/771hl xT5+wBPJtmXx5SMBv77PVZ30JfDOSXPDr9daDh2TylXtmrt108ufbBdO9om2bAwuTtu2IY59 +wbdFY/Zp7SXbdX723xNXkrG3UWV3+uEDLvImsv7Xd+J6XWtMzaQ/vo94E7XsZmp+4WmXmVp r/I1L70nN+XSZuH3rBfFM6MqPyuxFGckGmoxFxUnAgBs8uMZ4gMAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrCIsWRmVeSWpSXmKPExsVy+t/xu7opr23SDD5OVrS4+Hkhq8XnI8fZ LJ4ee8RusXL1USaLX18sLDpnb2C3uLCtj9Xi8q45bBYrDp1gtzi2QMxixu2lzBZzv0xltjj4 4QmrReOR92wWLXdMHfg9nhycx+SxZt4aRo8Fm0o9Fu95yeSxaVUnm8eLzTMZPXbfbGDz+LxJ LoAjSs+mKL+0JFUhI7+4xFYp2tDCSM/Q0kLPyMRSz9DYPNbKyFRJ384mJTUnsyy1SN8uQS9j 1fbrzAXrdCpWbXjM2sB4VbmLkZNDQsBE4sT0syxdjFwcQgJLGSWuretih0jISJyc1sAKYQtL /LnWxQZR9J5Ron/rRaYuRg4OXgE7ie+7PEBqWARUJHbt+MIIYvMKCEqcnPmEBcQWFZCXuH9r BthMYQE/iWVzLzKD2CICYRINPStYQWYyCxxklri+azPUFdMYJQ4veM4GUsUsIC5x68l8JhCb TcBQouttF1icU8BZYk7rSiaIGjOJrq1djBC2vMT2t3OYJzAKzUJyyCwko2YhaZmFpGUBI8sq RpHU0uLc9NxiI73ixNzi0rx0veT83E2MwOjeduznlh2MK1991DvEyMTBeIhRgoNZSYS3qsY6 TYg3JbGyKrUoP76oNCe1+BCjKTA0JjJLiSbnA9NLXkm8oZmBqaGJmaWBqaWZsZI4r2dBR6KQ QHpiSWp2ampBahFMHxMHp1QDk+WpyLf3Eg+unjIl7m1ApUYBz4LzN79PMe+4cZr55w0986Z7 9jOKEvtE9PmWSl5tvjjhjxvXm6DX11gyLcOsZjzaNGeOK/O7ot3PFogonDkgtI5ZcDk33zaL S2tvNJd12143bWnSk/vmIdTLVlGmc6s28LNr9urtK476tk6Re1KlVLXH7mZM+yWLV2rfd7Sx uHEe1l/yXj1jlp/x+S8Tj2WF+RZuWWxYaMK8ukqWZZmit/wN5fr53Fe/GLU5rv35xL/Hovuk TUrB84j0Yq57ZbJRnUli77dv3vNn7qrmkJTNEg7/5t37GB/+5t3t1cwfOu34P/1Kr3l3+PWG pHvZ6l8W5oR+De9ondytx+Q9W4mlOCPRUIu5qDgRACyAurJ3AwAA X-CMS-MailID: 20240509152732eucas1p1b71b1a26a0ad22e4b312fc67d31ce565 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-RootMTR: 20240509144704eucas1p2fe6bfb07a9b39f548e7db0f24e47eb0a X-EPHeader: CA CMS-TYPE: 201P X-CMS-RootMailID: 20240509144704eucas1p2fe6bfb07a9b39f548e7db0f24e47eb0a References: <20240509144616.938519-1-aleksander.lobakin@intel.com> On 09.05.2024 16:46, Alexander Lobakin wrote: > There are several reports that the DMA sync shortcut broke non-coherent > devices. > dev->dma_need_sync is false after the &device allocation and if a driver > didn't call dma_set_mask*(), it will still be false even if the device > is not DMA-coherent and thus needs synchronizing. Due to historical > reasons, there's still a lot of drivers not calling it. > Invert the boolean, so that the sync will be performed by default and > the shortcut will be enabled only when calling dma_set_mask*(). > > Reported-by: Marek Szyprowski > Closes: https://lore.kernel.org/lkml/46160534-5003-4809-a408-6b3a3f4921e9@samsung.com > Reported-by: Steven Price > Closes: https://lore.kernel.org/lkml/010686f5-3049-46a1-8230-7752a1b433ff@arm.com > Fixes: 32ba8b823252 ("dma: avoid redundant calls for sync operations") > Signed-off-by: Alexander Lobakin Tested-by: Marek Szyprowski > --- > include/linux/device.h | 4 ++-- > include/linux/dma-map-ops.h | 4 ++-- > include/linux/dma-mapping.h | 2 +- > kernel/dma/mapping.c | 10 +++++----- > kernel/dma/swiotlb.c | 2 +- > 5 files changed, 11 insertions(+), 11 deletions(-) > > diff --git a/include/linux/device.h b/include/linux/device.h > index ed95b829f05b..d4b50accff26 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -691,7 +691,7 @@ struct device_physical_location { > * and optionall (if the coherent mask is large enough) also > * for dma allocations. This flag is managed by the dma ops > * instance from ->dma_supported. > - * @dma_need_sync: The device needs performing DMA sync operations. > + * @dma_skip_sync: DMA sync operations can be skipped for coherent buffers. > * > * At the lowest level, every device in a Linux system is represented by an > * instance of struct device. The device structure contains the information > @@ -805,7 +805,7 @@ struct device { > bool dma_ops_bypass : 1; > #endif > #ifdef CONFIG_DMA_NEED_SYNC > - bool dma_need_sync:1; > + bool dma_skip_sync:1; > #endif > }; > > diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h > index 4893cb89cb52..5217b922d29f 100644 > --- a/include/linux/dma-map-ops.h > +++ b/include/linux/dma-map-ops.h > @@ -280,8 +280,8 @@ static inline void dma_reset_need_sync(struct device *dev) > { > #ifdef CONFIG_DMA_NEED_SYNC > /* Reset it only once so that the function can be called on hotpath */ > - if (unlikely(!dev->dma_need_sync)) > - dev->dma_need_sync = true; > + if (unlikely(dev->dma_skip_sync)) > + dev->dma_skip_sync = false; > #endif > } > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index eb4e15893b6c..f693aafe221f 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -295,7 +295,7 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr); > static inline bool dma_dev_need_sync(const struct device *dev) > { > /* Always call DMA sync operations when debugging is enabled */ > - return dev->dma_need_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG); > + return !dev->dma_skip_sync || IS_ENABLED(CONFIG_DMA_API_DEBUG); > } > > static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr, > diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c > index 3524bc92c37f..3f77c3f8d16d 100644 > --- a/kernel/dma/mapping.c > +++ b/kernel/dma/mapping.c > @@ -392,7 +392,7 @@ bool __dma_need_sync(struct device *dev, dma_addr_t dma_addr) > > if (dma_map_direct(dev, ops)) > /* > - * dma_need_sync could've been reset on first SWIOTLB buffer > + * dma_skip_sync could've been reset on first SWIOTLB buffer > * mapping, but @dma_addr is not necessary an SWIOTLB buffer. > * In this case, fall back to more granular check. > */ > @@ -407,20 +407,20 @@ static void dma_setup_need_sync(struct device *dev) > > if (dma_map_direct(dev, ops) || (ops->flags & DMA_F_CAN_SKIP_SYNC)) > /* > - * dma_need_sync will be reset to %true on first SWIOTLB buffer > + * dma_skip_sync will be reset to %false on first SWIOTLB buffer > * mapping, if any. During the device initialization, it's > * enough to check only for the DMA coherence. > */ > - dev->dma_need_sync = !dev_is_dma_coherent(dev); > + dev->dma_skip_sync = dev_is_dma_coherent(dev); > else if (!ops->sync_single_for_device && !ops->sync_single_for_cpu && > !ops->sync_sg_for_device && !ops->sync_sg_for_cpu) > /* > * Synchronization is not possible when none of DMA sync ops > * is set. > */ > - dev->dma_need_sync = false; > + dev->dma_skip_sync = true; > else > - dev->dma_need_sync = true; > + dev->dma_skip_sync = false; > } > #else /* !CONFIG_DMA_NEED_SYNC */ > static inline void dma_setup_need_sync(struct device *dev) { } > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index ae3e593eaadb..068134697cf1 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -1409,7 +1409,7 @@ phys_addr_t swiotlb_tbl_map_single(struct device *dev, phys_addr_t orig_addr, > } > > /* > - * If dma_need_sync wasn't set, reset it on first SWIOTLB buffer > + * If dma_skip_sync was set, reset it on first SWIOTLB buffer > * mapping to always sync SWIOTLB buffers. > */ > dma_reset_need_sync(dev); Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland