Hi Rengarajan, kernel test robot noticed the following build warnings: https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Rengarajan-S/8250-microchip-pci1xxxx-Rearranging-the-structure-declarations/20231215-234606 base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing patch link: https://lore.kernel.org/r/20231215151123.41812-5-rengarajan.s%40microchip.com patch subject: [PATCH v1 tty-next 4/4] 8250: microchip: pci1xxxx: Add Burst mode transmission support in uart driver for reading from FIFO config: i386-randconfig-141-20231216 (https://download.01.org/0day-ci/archive/20231216/202312161205.f6EpLZln-lkp@xxxxxxxxx/config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@xxxxxxxxx> | Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> | Closes: https://lore.kernel.org/r/202312161205.f6EpLZln-lkp@xxxxxxxxx/ smatch warnings: drivers/tty/serial/8250/8250_pci1xxxx.c:395 pci1xxxx_process_write_data() warn: should this be 'valid_burst_count == -1' vim +395 drivers/tty/serial/8250/8250_pci1xxxx.c eeaa9176002041 Rengarajan S 2023-12-15 351 static void pci1xxxx_process_write_data(struct uart_port *port, eeaa9176002041 Rengarajan S 2023-12-15 352 struct circ_buf *xmit, eeaa9176002041 Rengarajan S 2023-12-15 353 int *data_empty_count, eeaa9176002041 Rengarajan S 2023-12-15 354 u32 *valid_byte_count) eeaa9176002041 Rengarajan S 2023-12-15 355 { eeaa9176002041 Rengarajan S 2023-12-15 356 u32 valid_burst_count = *valid_byte_count / UART_BURST_SIZE; eeaa9176002041 Rengarajan S 2023-12-15 357 eeaa9176002041 Rengarajan S 2023-12-15 358 /* eeaa9176002041 Rengarajan S 2023-12-15 359 * Each transaction transfers data in DWORDs. If there are less than eeaa9176002041 Rengarajan S 2023-12-15 360 * four remaining valid_byte_count to transfer or if the circular eeaa9176002041 Rengarajan S 2023-12-15 361 * buffer has insufficient space for a DWORD, the data is transferred eeaa9176002041 Rengarajan S 2023-12-15 362 * one byte at a time. eeaa9176002041 Rengarajan S 2023-12-15 363 */ eeaa9176002041 Rengarajan S 2023-12-15 364 while (valid_burst_count--) { This loop ends with valid_burst_count set to -1. (Post operation). eeaa9176002041 Rengarajan S 2023-12-15 365 if (*data_empty_count - UART_BURST_SIZE < 0) eeaa9176002041 Rengarajan S 2023-12-15 366 break; eeaa9176002041 Rengarajan S 2023-12-15 367 if (xmit->tail > (UART_XMIT_SIZE - UART_BURST_SIZE)) eeaa9176002041 Rengarajan S 2023-12-15 368 break; eeaa9176002041 Rengarajan S 2023-12-15 369 writel(*(unsigned int *)&xmit->buf[xmit->tail], eeaa9176002041 Rengarajan S 2023-12-15 370 port->membase + UART_TX_BURST_FIFO); eeaa9176002041 Rengarajan S 2023-12-15 371 *valid_byte_count -= UART_BURST_SIZE; eeaa9176002041 Rengarajan S 2023-12-15 372 *data_empty_count -= UART_BURST_SIZE; eeaa9176002041 Rengarajan S 2023-12-15 373 xmit->tail = (xmit->tail + UART_BURST_SIZE) & eeaa9176002041 Rengarajan S 2023-12-15 374 (UART_XMIT_SIZE - 1); eeaa9176002041 Rengarajan S 2023-12-15 375 } eeaa9176002041 Rengarajan S 2023-12-15 376 eeaa9176002041 Rengarajan S 2023-12-15 377 while (*valid_byte_count--) { eeaa9176002041 Rengarajan S 2023-12-15 378 if (*data_empty_count - UART_BYTE_SIZE < 0) eeaa9176002041 Rengarajan S 2023-12-15 379 break; eeaa9176002041 Rengarajan S 2023-12-15 380 writeb(xmit->buf[xmit->tail], port->membase + eeaa9176002041 Rengarajan S 2023-12-15 381 UART_TX_BYTE_FIFO); eeaa9176002041 Rengarajan S 2023-12-15 382 *data_empty_count -= UART_BYTE_SIZE; eeaa9176002041 Rengarajan S 2023-12-15 383 eeaa9176002041 Rengarajan S 2023-12-15 384 /* eeaa9176002041 Rengarajan S 2023-12-15 385 * When the tail of the circular buffer is reached, the next eeaa9176002041 Rengarajan S 2023-12-15 386 * byte is transferred to the beginning of the buffer. eeaa9176002041 Rengarajan S 2023-12-15 387 */ eeaa9176002041 Rengarajan S 2023-12-15 388 xmit->tail = (xmit->tail + UART_BYTE_SIZE) & eeaa9176002041 Rengarajan S 2023-12-15 389 (UART_XMIT_SIZE - 1); eeaa9176002041 Rengarajan S 2023-12-15 390 eeaa9176002041 Rengarajan S 2023-12-15 391 /* eeaa9176002041 Rengarajan S 2023-12-15 392 * If there are any pending burst count, data is handled by eeaa9176002041 Rengarajan S 2023-12-15 393 * transmitting DWORDs at a time. eeaa9176002041 Rengarajan S 2023-12-15 394 */ eeaa9176002041 Rengarajan S 2023-12-15 @395 if (valid_burst_count && (xmit->tail < ^^^^^^^^^^^^^^^^^ So this test should be if valid_burst_count != -1. Or if valid_burst_count != UINT_MAX because it's unsigned... eeaa9176002041 Rengarajan S 2023-12-15 396 (UART_XMIT_SIZE - UART_BURST_SIZE))) eeaa9176002041 Rengarajan S 2023-12-15 397 break; eeaa9176002041 Rengarajan S 2023-12-15 398 } eeaa9176002041 Rengarajan S 2023-12-15 399 } -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
