async_pq: Remove VLA usage

In the quest to remove VLAs from the kernel[1], this adjusts the
allocation of coefs and blocks to use the existing maximum values
(with one new define, MAX_DISKS for coefs, and a reuse of the
existing NDISKS for blocks).

[1] https://lkml.org/lkml/2018/3/7/621

Signed-off-by: Kyle Spiers <ksspiers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
index 56bd612927ab1688d324fb056e9ff6d2a2f3e037..80dc567801ec0006c395c7f8b796e8fe0f128ef1 100644 (file)
--- a/crypto/async_tx/async_pq.c
+++ b/crypto/async_tx/async_pq.c
@@ -42,6 +42,8 @@ static struct page *pq_scribble_page;
 #define P(b, d) (b[d-2])
 #define Q(b, d) (b[d-1])
 
+#define MAX_DISKS 255
+
 /**
  * do_async_gen_syndrome - asynchronously calculate P and/or Q
  */
@@ -184,7 +186,7 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
        struct dma_device *device = chan ? chan->device : NULL;
        struct dmaengine_unmap_data *unmap = NULL;
 
-       BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks)));
+       BUG_ON(disks > MAX_DISKS || !(P(blocks, disks) || Q(blocks, disks)));
 
        if (device)
                unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);
@@ -196,7 +198,7 @@ async_gen_syndrome(struct page **blocks, unsigned int offset, int disks,
            is_dma_pq_aligned(device, offset, 0, len)) {
                struct dma_async_tx_descriptor *tx;
                enum dma_ctrl_flags dma_flags = 0;
-               unsigned char coefs[src_cnt];
+               unsigned char coefs[MAX_DISKS];
                int i, j;
 
                /* run the p+q asynchronously */
@@ -299,11 +301,11 @@ async_syndrome_val(struct page **blocks, unsigned int offset, int disks,
        struct dma_chan *chan = pq_val_chan(submit, blocks, disks, len);
        struct dma_device *device = chan ? chan->device : NULL;
        struct dma_async_tx_descriptor *tx;
-       unsigned char coefs[disks-2];
+       unsigned char coefs[MAX_DISKS];
        enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0;
        struct dmaengine_unmap_data *unmap = NULL;
 
-       BUG_ON(disks < 4);
+       BUG_ON(disks < 4 || disks > MAX_DISKS);
 
        if (device)
                unmap = dmaengine_get_unmap_data(device->dev, disks, GFP_NOWAIT);

diff --git a/crypto/async_tx/raid6test.c b/crypto/async_tx/raid6test.c
index dad95f45b88f6566afc62df645151d3a2ae60092..a5edaabae12a1ea1b90b3696209c54624ce8cc7d 100644 (file)
--- a/crypto/async_tx/raid6test.c
+++ b/crypto/async_tx/raid6test.c
@@ -81,11 +81,13 @@ static void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, stru
                        init_async_submit(&submit, 0, NULL, NULL, NULL, addr_conv);
                        tx = async_gen_syndrome(ptrs, 0, disks, bytes, &submit);
                } else {
-                       struct page *blocks[disks];
+                       struct page *blocks[NDISKS];
                        struct page *dest;
                        int count = 0;
                        int i;
 
+                       BUG_ON(disks > NDISKS);
+
                        /* data+Q failure.  Reconstruct data from P,
                         * then rebuild syndrome
                         */