From 0bb322be5d389c00740d884351d4ba08fca938aa Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Mon, 25 Mar 2024 17:14:09 -0500 Subject: driver core: Remove unused platform_notify, platform_notify_remove The "platform_notify" and "platform_notify_remove" hooks have been unused since 00ba9357d189 ("ARM: ixp4xx: Drop custom DMA coherency and bouncing"). Remove "platform_notify" and "platform_notify_remove". No functional change intended. Signed-off-by: Bjorn Helgaas Cc: Heikki Krogerus Cc: Linus Walleij Reviewed-by: Andy Shevchenko Acked-by: Rafael J. Wysocki Link: https://lore.kernel.org/r/20240325221409.1457036-1-helgaas@kernel.org Signed-off-by: Greg Kroah-Hartman --- include/linux/device.h | 11 ----------- 1 file changed, 11 deletions(-) (limited to 'include/linux/device.h') diff --git a/include/linux/device.h b/include/linux/device.h index 97c4b046c09d..c515ba5756e4 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1206,17 +1206,6 @@ int __must_check devm_device_add_groups(struct device *dev, int __must_check devm_device_add_group(struct device *dev, const struct attribute_group *grp); -/* - * Platform "fixup" functions - allow the platform to have their say - * about devices and actions that the general device layer doesn't - * know about. - */ -/* Notify platform of device discovery */ -extern int (*platform_notify)(struct device *dev); - -extern int (*platform_notify_remove)(struct device *dev); - - /* * get_device - atomically increment the reference count for the device. * -- cgit v1.2.3 From 3cc50d07be10f67aff836f8247a240ec132c6a67 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Sat, 20 Apr 2024 22:00:01 +0200 Subject: driver core: Add device_show_string() helper for sysfs attributes For drivers wishing to expose an unsigned long, int or bool at a static memory location in sysfs, the driver core provides ready-made helpers such as device_show_ulong() to be used as ->show() callback. Some drivers need to expose a string and so far they all provide their own ->show() implementation. arch/powerpc/perf/hv-24x7.c went so far as to create a device_show_string() helper but kept it private. Make it public for reuse by other drivers. The pattern seems to be sufficiently frequent to merit a public helper. Add a DEVICE_STRING_ATTR_RO() macro in line with the existing DEVICE_ULONG_ATTR() and similar macros to ease declaration of string attributes. Signed-off-by: Lukas Wunner Acked-by: Michael Ellerman Link: https://lore.kernel.org/r/2e3eaaf2600bb55c0415c23ba301e809403a7aa2.1713608122.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman --- include/linux/device.h | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'include/linux/device.h') diff --git a/include/linux/device.h b/include/linux/device.h index 07f4d2af1e3c..b6b6ff881a3f 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -132,6 +132,8 @@ ssize_t device_show_bool(struct device *dev, struct device_attribute *attr, char *buf); ssize_t device_store_bool(struct device *dev, struct device_attribute *attr, const char *buf, size_t count); +ssize_t device_show_string(struct device *dev, struct device_attribute *attr, + char *buf); /** * DEVICE_ATTR - Define a device attribute. @@ -251,6 +253,19 @@ ssize_t device_store_bool(struct device *dev, struct device_attribute *attr, struct dev_ext_attribute dev_attr_##_name = \ { __ATTR(_name, _mode, device_show_bool, device_store_bool), &(_var) } +/** + * DEVICE_STRING_ATTR_RO - Define a device attribute backed by a r/o string. + * @_name: Attribute name. + * @_mode: File mode. + * @_var: Identifier of string. + * + * Like DEVICE_ULONG_ATTR(), but @_var is a string. Because the length of the + * string allocation is unknown, the attribute must be read-only. + */ +#define DEVICE_STRING_ATTR_RO(_name, _mode, _var) \ + struct dev_ext_attribute dev_attr_##_name = \ + { __ATTR(_name, (_mode) & ~0222, device_show_string, NULL), (_var) } + #define DEVICE_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \ struct device_attribute dev_attr_##_name = \ __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) -- cgit v1.2.3 From f406c8e4b770ca3b0df84a17349e13f2b6b07d10 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Tue, 7 May 2024 13:20:21 +0200 Subject: dma: avoid redundant calls for sync operations Quite often, devices do not need dma_sync operations on x86_64 at least. Indeed, when dev_is_dma_coherent(dev) is true and dev_use_swiotlb(dev) is false, iommu_dma_sync_single_for_cpu() and friends do nothing. However, indirectly calling them when CONFIG_RETPOLINE=y consumes about 10% of cycles on a cpu receiving packets from softirq at ~100Gbit rate. Even if/when CONFIG_RETPOLINE is not set, there is a cost of about 3%. Add dev->need_dma_sync boolean and turn it off during the device initialization (dma_set_mask()) depending on the setup: dev_is_dma_coherent() for the direct DMA, !(sync_single_for_device || sync_single_for_cpu) or the new dma_map_ops flag, %DMA_F_CAN_SKIP_SYNC, advertised for non-NULL DMA ops. Then later, if/when swiotlb is used for the first time, the flag is reset back to on, from swiotlb_tbl_map_single(). On iavf, the UDP trafficgen with XDP_DROP in skb mode test shows +3-5% increase for direct DMA. Suggested-by: Christoph Hellwig # direct DMA shortcut Co-developed-by: Eric Dumazet Signed-off-by: Eric Dumazet Signed-off-by: Alexander Lobakin Signed-off-by: Christoph Hellwig --- include/linux/device.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux/device.h') diff --git a/include/linux/device.h b/include/linux/device.h index b9f5464f44ed..ed95b829f05b 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -691,6 +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. * * At the lowest level, every device in a Linux system is represented by an * instance of struct device. The device structure contains the information @@ -803,6 +804,9 @@ struct device { #ifdef CONFIG_DMA_OPS_BYPASS bool dma_ops_bypass : 1; #endif +#ifdef CONFIG_DMA_NEED_SYNC + bool dma_need_sync:1; +#endif }; /** -- cgit v1.2.3 From a6016aac5252da9d22a4dc0b98121b0acdf6d2f5 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Thu, 9 May 2024 16:46:16 +0200 Subject: dma: fix DMA sync for drivers not calling dma_set_mask*() 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: Steven Price Closes: https://lore.kernel.org/lkml/010686f5-3049-46a1-8230-7752a1b433ff@arm.com Reported-by: Marek Szyprowski Closes: https://lore.kernel.org/lkml/46160534-5003-4809-a408-6b3a3f4921e9@samsung.com Fixes: f406c8e4b770. ("dma: avoid redundant calls for sync operations") Signed-off-by: Alexander Lobakin Signed-off-by: Christoph Hellwig Tested-by: Steven Price Tested-by: Marek Szyprowski --- include/linux/device.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux/device.h') 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 }; -- cgit v1.2.3