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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-08 09:48:04 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-08 09:48:04 -0800
commite4ff63b437e29d305dfc17eed69559354ad48167 (patch)
tree42f93bb8aa645eb0474e8d6b7d00b6609f44060b
parentMerge branch 'i2c/for-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux (diff)
parentswiotlb: drop pointless static qualifier in swiotlb_create_debugfs() (diff)
downloadlinux-dev-e4ff63b437e29d305dfc17eed69559354ad48167.tar.xz
linux-dev-e4ff63b437e29d305dfc17eed69559354ad48167.zip
Merge branch 'stable/for-linus-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb
Pull swiotlb updates from Konrad Rzeszutek Wilk: "Expands the SWIOTLB to have debugfs support (along with bug-fixes), and a tiny fix" * 'stable/for-linus-5.1' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb: swiotlb: drop pointless static qualifier in swiotlb_create_debugfs() swiotlb: checking whether swiotlb buffer is full with io_tlb_used swiotlb: add debugfs to track swiotlb buffer usage swiotlb: fix comment on swiotlb_bounce()
-rw-r--r--kernel/dma/swiotlb.c50
1 files changed, 49 insertions, 1 deletions
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 6d0236bd3929..a9ad02d4d84e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -34,6 +34,9 @@
#include <linux/scatterlist.h>
#include <linux/mem_encrypt.h>
#include <linux/set_memory.h>
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#endif
#include <asm/io.h>
#include <asm/dma.h>
@@ -73,6 +76,11 @@ phys_addr_t io_tlb_start, io_tlb_end;
static unsigned long io_tlb_nslabs;
/*
+ * The number of used IO TLB block
+ */
+static unsigned long io_tlb_used;
+
+/*
* This is a free list describing the number of free entries available from
* each index
*/
@@ -385,7 +393,7 @@ void __init swiotlb_exit(void)
}
/*
- * Bounce: copy the swiotlb buffer back to the original dma location
+ * Bounce: copy the swiotlb buffer from or back to the original dma location
*/
static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir)
@@ -475,6 +483,10 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
* request and allocate a buffer from that IO TLB pool.
*/
spin_lock_irqsave(&io_tlb_lock, flags);
+
+ if (unlikely(nslots > io_tlb_nslabs - io_tlb_used))
+ goto not_found;
+
index = ALIGN(io_tlb_index, stride);
if (index >= io_tlb_nslabs)
index = 0;
@@ -524,6 +536,7 @@ not_found:
dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
return DMA_MAPPING_ERROR;
found:
+ io_tlb_used += nslots;
spin_unlock_irqrestore(&io_tlb_lock, flags);
/*
@@ -584,6 +597,8 @@ void swiotlb_tbl_unmap_single(struct device *hwdev, phys_addr_t tlb_addr,
*/
for (i = index - 1; (OFFSET(i, IO_TLB_SEGSIZE) != IO_TLB_SEGSIZE -1) && io_tlb_list[i]; i--)
io_tlb_list[i] = ++count;
+
+ io_tlb_used -= nslots;
}
spin_unlock_irqrestore(&io_tlb_lock, flags);
}
@@ -650,3 +665,36 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr,
return true;
}
+
+#ifdef CONFIG_DEBUG_FS
+
+static int __init swiotlb_create_debugfs(void)
+{
+ struct dentry *d_swiotlb_usage;
+ struct dentry *ent;
+
+ d_swiotlb_usage = debugfs_create_dir("swiotlb", NULL);
+
+ if (!d_swiotlb_usage)
+ return -ENOMEM;
+
+ ent = debugfs_create_ulong("io_tlb_nslabs", 0400,
+ d_swiotlb_usage, &io_tlb_nslabs);
+ if (!ent)
+ goto fail;
+
+ ent = debugfs_create_ulong("io_tlb_used", 0400,
+ d_swiotlb_usage, &io_tlb_used);
+ if (!ent)
+ goto fail;
+
+ return 0;
+
+fail:
+ debugfs_remove_recursive(d_swiotlb_usage);
+ return -ENOMEM;
+}
+
+late_initcall(swiotlb_create_debugfs);
+
+#endif