tpm: use GFP_KERNEL instead of GFP_HIGHMEM for tpm_buf

The current code uses GFP_HIGHMEM, which is wrong because GFP_HIGHMEM
(on 32 bit systems) is memory ordinarily inaccessible to the kernel
and should only be used for allocations affecting userspace.  In order
to make highmem visible to the kernel on 32 bit it has to be kmapped,
which consumes valuable entries in the kmap region.  Since the tpm_buf
is only ever used in the kernel, switch to using a GFP_KERNEL
allocation so as not to waste kmap space on 32 bits.

Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 80bca88b1f9196e9f4dacc19462b8bbd4d869767..0d1fd37d621893c373034c803672fec9ce3904ec 100644 (file)
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -282,7 +282,6 @@ enum tpm_buf_flags {
 };
 
 struct tpm_buf {
-       struct page *data_page;
        unsigned int flags;
        u8 *data;
 };
@@ -298,20 +297,18 @@ static inline void tpm_buf_reset(struct tpm_buf *buf, u16 tag, u32 ordinal)
 
 static inline int tpm_buf_init(struct tpm_buf *buf, u16 tag, u32 ordinal)
 {
-       buf->data_page = alloc_page(GFP_HIGHUSER);
-       if (!buf->data_page)
+       buf->data = (u8 *)__get_free_page(GFP_KERNEL);
+       if (!buf->data)
                return -ENOMEM;
 
        buf->flags = 0;
-       buf->data = kmap(buf->data_page);
        tpm_buf_reset(buf, tag, ordinal);
        return 0;
 }
 
 static inline void tpm_buf_destroy(struct tpm_buf *buf)
 {
-       kunmap(buf->data_page);
-       __free_page(buf->data_page);
+       free_page((unsigned long)buf->data);
 }
 
 static inline u32 tpm_buf_length(struct tpm_buf *buf)