From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Dan Williams <dan.j.williams@intel.com>,
Arnd Bergmann <arnd@arndb.de>, Dave Chinner <david@fromorbit.com>
Cc: linux-kernel@vger.kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Matthew Wilcox <willy@infradead.org>,
Russell King <linux@armlinux.org.uk>,
linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-xfs@vger.kernel.org, dm-devel@lists.linux.dev,
nvdimm@lists.linux.dev, linux-s390@vger.kernel.org
Subject: [PATCH v5 6/8] dax: Check for data cache aliasing at runtime
Date: Mon, 12 Feb 2024 11:30:59 -0500 [thread overview]
Message-ID: <20240212163101.19614-7-mathieu.desnoyers@efficios.com> (raw)
In-Reply-To: <20240212163101.19614-1-mathieu.desnoyers@efficios.com>
Replace the following fs/Kconfig:FS_DAX dependency:
depends on !(ARM || MIPS || SPARC)
By a runtime check within alloc_dax(). This runtime check returns
ERR_PTR(-EOPNOTSUPP) if the @ops parameter is non-NULL (which means
the kernel is using an aliased mapping) on an architecture which
has data cache aliasing.
Change the return value from NULL to PTR_ERR(-EOPNOTSUPP) for
CONFIG_DAX=n for consistency.
This is done in preparation for using cpu_dcache_is_aliasing() in a
following change which will properly support architectures which detect
data cache aliasing at runtime.
Fixes: d92576f1167c ("dax: does not work correctly with virtual aliasing caches")
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arch@vger.kernel.org
Cc: linux-cxl@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: dm-devel@lists.linux.dev
Cc: nvdimm@lists.linux.dev
---
drivers/dax/super.c | 10 ++++++++++
fs/Kconfig | 1 -
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 205b888d45bf..ce5bffa86bba 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -450,6 +450,16 @@ struct dax_device *alloc_dax(void *private, const struct dax_operations *ops)
dev_t devt;
int minor;
+ /*
+ * Unavailable on architectures with virtually aliased data caches,
+ * except for device-dax (NULL operations pointer), which does
+ * not use aliased mappings from the kernel.
+ */
+ if (ops && (IS_ENABLED(CONFIG_ARM) ||
+ IS_ENABLED(CONFIG_MIPS) ||
+ IS_ENABLED(CONFIG_SPARC)))
+ return ERR_PTR(-EOPNOTSUPP);
+
if (WARN_ON_ONCE(ops && !ops->zero_page_range))
return ERR_PTR(-EINVAL);
diff --git a/fs/Kconfig b/fs/Kconfig
index 42837617a55b..e5efdb3b276b 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -56,7 +56,6 @@ endif # BLOCK
config FS_DAX
bool "File system based Direct Access (DAX) support"
depends on MMU
- depends on !(ARM || MIPS || SPARC)
depends on ZONE_DEVICE || FS_DAX_LIMITED
select FS_IOMAP
select DAX
--
2.39.2
next prev parent reply other threads:[~2024-02-12 16:31 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-12 16:30 [PATCH v5 0/8] Introduce cpu_dcache_is_aliasing() to fix DAX regression Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 1/8] dax: alloc_dax() return ERR_PTR(-EOPNOTSUPP) for CONFIG_DAX=n Mathieu Desnoyers
2024-02-13 6:32 ` Lukas Wunner
2024-02-13 19:07 ` Dan Williams
2024-02-13 20:07 ` Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 2/8] nvdimm/pmem: Treat alloc_dax() -EOPNOTSUPP failure as non-fatal Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 3/8] dm: " Mathieu Desnoyers
2024-02-12 16:30 ` [PATCH v5 4/8] dcssblk: Handle alloc_dax() -EOPNOTSUPP failure Mathieu Desnoyers
2024-02-13 11:18 ` Heiko Carstens
2024-02-12 16:30 ` [PATCH v5 5/8] virtio: Treat alloc_dax() -EOPNOTSUPP failure as non-fatal Mathieu Desnoyers
2024-02-12 22:04 ` Dan Williams
2024-02-12 22:08 ` Linus Torvalds
2024-02-12 23:02 ` Dan Williams
2024-02-13 6:18 ` Lukas Wunner
2024-02-13 18:56 ` Dan Williams
2024-02-13 20:25 ` Mathieu Desnoyers
2024-02-13 6:25 ` Lukas Wunner
2024-02-13 19:46 ` Mathieu Desnoyers
2024-02-14 6:59 ` Greg Kroah-Hartman
2024-02-12 16:30 ` Mathieu Desnoyers [this message]
2024-02-12 16:31 ` [PATCH v5 7/8] Introduce cpu_dcache_is_aliasing() across all architectures Mathieu Desnoyers
2024-02-12 16:31 ` [PATCH v5 8/8] dax: Fix incorrect list of data cache aliasing architectures Mathieu Desnoyers
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