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[149.14.88.26]) by smtp.gmail.com with ESMTPSA id nc5-20020a0562142dc500b00685e2ffcaf5sm2958704qvb.38.2024.01.23.01.44.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 Jan 2024 01:44:51 -0800 (PST) From: Philipp Stanner To: Jonathan Corbet , Hans de Goede , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Bjorn Helgaas , Philipp Stanner , Sam Ravnborg , dakr@redhat.com Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-pci@vger.kernel.org Subject: [PATCH v2 03/10] PCI: warn users about complicated devres nature Date: Tue, 23 Jan 2024 10:43:00 +0100 Message-ID: <20240123094317.15958-4-pstanner@redhat.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240123094317.15958-1-pstanner@redhat.com> References: <20240123094317.15958-1-pstanner@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1788874175360021765 X-GMAIL-MSGID: 1788874175360021765 The PCI region-request functions become managed functions when pcim_enable_device() has been called previously instead of pci_enable_device(). This has already caused bugs by confusing users, who came to believe that all pci functions, such as pci_iomap_range(), suddenly are managed that way. This is not the case. Add comments to the relevant functions' docstrings that warn users about this behavior. Signed-off-by: Philipp Stanner --- drivers/pci/iomap.c | 18 ++++++++++++++ drivers/pci/pci.c | 60 ++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 77 insertions(+), 1 deletion(-) diff --git a/drivers/pci/iomap.c b/drivers/pci/iomap.c index b7faf22ec8f5..0b7fcc2f7a49 100644 --- a/drivers/pci/iomap.c +++ b/drivers/pci/iomap.c @@ -23,6 +23,11 @@ * * @maxlen specifies the maximum length to map. If you want to get access to * the complete BAR from offset to the end, pass %0 here. + * + * NOTE: + * This function is never managed, even if you initialized with + * pcim_enable_device(). + * If you need automatic cleanup, use pcim_iomap_range(). * */ void __iomem *pci_iomap_range(struct pci_dev *dev, int bar, @@ -63,6 +68,10 @@ EXPORT_SYMBOL(pci_iomap_range); * * @maxlen specifies the maximum length to map. If you want to get access to * the complete BAR from offset to the end, pass %0 here. + * + * NOTE: + * This function is never managed, even if you initialized with + * pcim_enable_device(). * */ void __iomem *pci_iomap_wc_range(struct pci_dev *dev, int bar, @@ -106,6 +115,11 @@ EXPORT_SYMBOL_GPL(pci_iomap_wc_range); * * @maxlen specifies the maximum length to map. If you want to get access to * the complete BAR without checking for its length first, pass %0 here. + * + * NOTE: + * This function is never managed, even if you initialized with + * pcim_enable_device(). + * If you need automatic cleanup, use pcim_iomap(). * */ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen) { @@ -127,6 +141,10 @@ EXPORT_SYMBOL(pci_iomap); * * @maxlen specifies the maximum length to map. If you want to get access to * the complete BAR without checking for its length first, pass %0 here. + * + * NOTE: + * This function is never managed, even if you initialized with + * pcim_enable_device(). * */ void __iomem *pci_iomap_wc(struct pci_dev *dev, int bar, unsigned long maxlen) { diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 2899df77a285..7ca860acf351 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3907,6 +3907,8 @@ EXPORT_SYMBOL(pci_release_region); * @res_name: Name to be associated with resource. * @exclusive: whether the region access is exclusive or not * + * Returns: 0 on success, negative error code on failure. + * * Mark the PCI region associated with PCI device @pdev BAR @bar as * being reserved by owner @res_name. Do not access any * address inside the PCI regions unless this call returns @@ -3918,6 +3920,13 @@ EXPORT_SYMBOL(pci_release_region); * * Returns 0 on success, or %EBUSY on error. A warning * message is also printed on failure. + * + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! If you need to implement a new pci + * function that does automatic cleanup, write a new pcim_* function that uses + * devres directly. */ static int __pci_request_region(struct pci_dev *pdev, int bar, const char *res_name, int exclusive) @@ -3966,6 +3975,8 @@ static int __pci_request_region(struct pci_dev *pdev, int bar, * @bar: BAR to be reserved * @res_name: Name to be associated with resource * + * Returns: 0 on success, negative error code on failure. + * * Mark the PCI region associated with PCI device @pdev BAR @bar as * being reserved by owner @res_name. Do not access any * address inside the PCI regions unless this call returns @@ -3973,6 +3984,12 @@ static int __pci_request_region(struct pci_dev *pdev, int bar, * * Returns 0 on success, or %EBUSY on error. A warning * message is also printed on failure. + * + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! If you want managed cleanup, use the + * pcim_* functions instead. */ int pci_request_region(struct pci_dev *pdev, int bar, const char *res_name) { @@ -3998,6 +4015,13 @@ void pci_release_selected_regions(struct pci_dev *pdev, int bars) } EXPORT_SYMBOL(pci_release_selected_regions); +/* + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! If you want managed cleanup, use the + * pcim_* functions instead. + */ static int __pci_request_selected_regions(struct pci_dev *pdev, int bars, const char *res_name, int excl) { @@ -4023,6 +4047,14 @@ static int __pci_request_selected_regions(struct pci_dev *pdev, int bars, * @pdev: PCI device whose resources are to be reserved * @bars: Bitmask of BARs to be requested * @res_name: Name to be associated with resource + * + * Returns: 0 on success, negative error code on failure. + * + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! If you want managed cleanup, use the + * pcim_* functions instead. */ int pci_request_selected_regions(struct pci_dev *pdev, int bars, const char *res_name) @@ -4031,6 +4063,20 @@ int pci_request_selected_regions(struct pci_dev *pdev, int bars, } EXPORT_SYMBOL(pci_request_selected_regions); +/** + * pci_request_selected_regions_exclusive - Request regions exclusively + * @pdev: PCI device to request regions from + * @bars: bit mask of bars to request + * @res_name: name to be associated with the requests + * + * Returns: 0 on success, negative error code on failure. + * + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! If you want managed cleanup, use the + * pcim_* functions instead. + */ int pci_request_selected_regions_exclusive(struct pci_dev *pdev, int bars, const char *res_name) { @@ -4048,7 +4094,6 @@ EXPORT_SYMBOL(pci_request_selected_regions_exclusive); * successful call to pci_request_regions(). Call this function only * after all use of the PCI regions has ceased. */ - void pci_release_regions(struct pci_dev *pdev) { pci_release_selected_regions(pdev, (1 << PCI_STD_NUM_BARS) - 1); @@ -4080,6 +4125,8 @@ EXPORT_SYMBOL(pci_request_regions); * @pdev: PCI device whose resources are to be reserved * @res_name: Name to be associated with resource. * + * Returns: 0 on success, negative error code on failure. + * * Mark all PCI regions associated with PCI device @pdev as being reserved * by owner @res_name. Do not access any address inside the PCI regions * unless this call returns successfully. @@ -4089,6 +4136,12 @@ EXPORT_SYMBOL(pci_request_regions); * * Returns 0 on success, or %EBUSY on error. A warning message is also * printed on failure. + * + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! If you want managed cleanup, use the + * pcim_* functions instead. */ int pci_request_regions_exclusive(struct pci_dev *pdev, const char *res_name) { @@ -4420,6 +4473,11 @@ void pci_disable_parity(struct pci_dev *dev) * @enable: boolean: whether to enable or disable PCI INTx * * Enables/disables PCI INTx for device @pdev + * + * NOTE: + * This is a "hybrid" function: Its normally unmanaged, but becomes managed + * when pcim_enable_device() has been called in advance. + * This hybrid feature is DEPRECATED! */ void pci_intx(struct pci_dev *pdev, int enable) {