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vfio-mdev/samples: Use u8 instead of char for handle functions
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Clang warns:

samples/vfio-mdev/mtty.c:592:39: warning: implicit conversion from 'int'
to 'char' changes value from 162 to -94 [-Wconstant-conversion]
                *buf = UART_MSR_DSR | UART_MSR_DDSR | UART_MSR_DCD;
                     ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~
1 warning generated.

Turns out that all uses of buf in this function ultimately end up stored
or cast to an unsigned type. Just use u8, which has the same number of
bits but can store this larger number so Clang no longer warns.

Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Alex Williamson <[email protected]>
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@nathanchance @awilliam
nathanchance authored and awilliam committed Dec 17, 2018
1 parent 9422f58 commit 8ba35b3
Showing 1 changed file with 13 additions and 13 deletions.
26 changes: 13 additions & 13 deletions samples/vfio-mdev/mtty.c
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Original file line number Diff line number Diff line change
Expand Up @@ -171,7 +171,7 @@ static struct mdev_state *find_mdev_state_by_uuid(uuid_le uuid)
return NULL;
}

void dump_buffer(char *buf, uint32_t count)
void dump_buffer(u8 *buf, uint32_t count)
{
#if defined(DEBUG)
int i;
Expand Down Expand Up @@ -250,7 +250,7 @@ static void mtty_create_config_space(struct mdev_state *mdev_state)
}

static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset,
char *buf, u32 count)
u8 *buf, u32 count)
{
u32 cfg_addr, bar_mask, bar_index = 0;

Expand Down Expand Up @@ -304,7 +304,7 @@ static void handle_pci_cfg_write(struct mdev_state *mdev_state, u16 offset,
}

static void handle_bar_write(unsigned int index, struct mdev_state *mdev_state,
u16 offset, char *buf, u32 count)
u16 offset, u8 *buf, u32 count)
{
u8 data = *buf;

Expand Down Expand Up @@ -475,7 +475,7 @@ static void handle_bar_write(unsigned int index, struct mdev_state *mdev_state,
}

static void handle_bar_read(unsigned int index, struct mdev_state *mdev_state,
u16 offset, char *buf, u32 count)
u16 offset, u8 *buf, u32 count)
{
/* Handle read requests by guest */
switch (offset) {
Expand Down Expand Up @@ -650,7 +650,7 @@ static void mdev_read_base(struct mdev_state *mdev_state)
}
}

static ssize_t mdev_access(struct mdev_device *mdev, char *buf, size_t count,
static ssize_t mdev_access(struct mdev_device *mdev, u8 *buf, size_t count,
loff_t pos, bool is_write)
{
struct mdev_state *mdev_state;
Expand Down Expand Up @@ -698,7 +698,7 @@ static ssize_t mdev_access(struct mdev_device *mdev, char *buf, size_t count,
#if defined(DEBUG_REGS)
pr_info("%s: BAR%d WR @0x%llx %s val:0x%02x dlab:%d\n",
__func__, index, offset, wr_reg[offset],
(u8)*buf, mdev_state->s[index].dlab);
*buf, mdev_state->s[index].dlab);
#endif
handle_bar_write(index, mdev_state, offset, buf, count);
} else {
Expand All @@ -708,7 +708,7 @@ static ssize_t mdev_access(struct mdev_device *mdev, char *buf, size_t count,
#if defined(DEBUG_REGS)
pr_info("%s: BAR%d RD @0x%llx %s val:0x%02x dlab:%d\n",
__func__, index, offset, rd_reg[offset],
(u8)*buf, mdev_state->s[index].dlab);
*buf, mdev_state->s[index].dlab);
#endif
}
break;
Expand Down Expand Up @@ -827,7 +827,7 @@ ssize_t mtty_read(struct mdev_device *mdev, char __user *buf, size_t count,
if (count >= 4 && !(*ppos % 4)) {
u32 val;

ret = mdev_access(mdev, (char *)&val, sizeof(val),
ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
*ppos, false);
if (ret <= 0)
goto read_err;
Expand All @@ -839,7 +839,7 @@ ssize_t mtty_read(struct mdev_device *mdev, char __user *buf, size_t count,
} else if (count >= 2 && !(*ppos % 2)) {
u16 val;

ret = mdev_access(mdev, (char *)&val, sizeof(val),
ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
*ppos, false);
if (ret <= 0)
goto read_err;
Expand All @@ -851,7 +851,7 @@ ssize_t mtty_read(struct mdev_device *mdev, char __user *buf, size_t count,
} else {
u8 val;

ret = mdev_access(mdev, (char *)&val, sizeof(val),
ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
*ppos, false);
if (ret <= 0)
goto read_err;
Expand Down Expand Up @@ -889,7 +889,7 @@ ssize_t mtty_write(struct mdev_device *mdev, const char __user *buf,
if (copy_from_user(&val, buf, sizeof(val)))
goto write_err;

ret = mdev_access(mdev, (char *)&val, sizeof(val),
ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
*ppos, true);
if (ret <= 0)
goto write_err;
Expand All @@ -901,7 +901,7 @@ ssize_t mtty_write(struct mdev_device *mdev, const char __user *buf,
if (copy_from_user(&val, buf, sizeof(val)))
goto write_err;

ret = mdev_access(mdev, (char *)&val, sizeof(val),
ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
*ppos, true);
if (ret <= 0)
goto write_err;
Expand All @@ -913,7 +913,7 @@ ssize_t mtty_write(struct mdev_device *mdev, const char __user *buf,
if (copy_from_user(&val, buf, sizeof(val)))
goto write_err;

ret = mdev_access(mdev, (char *)&val, sizeof(val),
ret = mdev_access(mdev, (u8 *)&val, sizeof(val),
*ppos, true);
if (ret <= 0)
goto write_err;
Expand Down

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